Correction: Regulation of ubiquitin-like with plant homeodomain and RING finger domain 1 (UHRF1) protein stability by heat shock protein 90 chaperone machinery. [Additions and Corrections]
VOLUME 291 (2016) PAGES 20125–20135Figs. 1, 2, 3, and 5 did not match the versions of the figures that were published as a Paper in Press on August 3, 2016. Additionally, the figure legend to Fig. 3 was incorrect. The text for panel D should be removed and replaced with the text for panel E. These errors have now been corrected and do not affect the results or conclusions of this work.jbc;293/45/17661/F1F1F1Figure 1.jbc;293/45/17661/F2F2F2Figure 2.jbc;293/45/17661/F3F3F3Figure 3.jbc;293/45/17661/F5F4F5Figure 5. (Source: Journal of Biological Chemistry)
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Guangjin Ding, Peilin Chen, Hui Zhang, Xiaojie Huang, Yi Zang, Jiwen Li, Jia Li, Jiemin Wong Tags: Additions and Corrections Source Type: research

The microRNA-23a cluster regulates the developmental HoxA cluster function during osteoblast differentiation [Cell Biology]
We examined this regulation in preosteoblasts and in a novel miR-23a cluster knockdown mouse model. Overexpression and knockdown of the miR-23a cluster in preosteoblasts decreased and increased, respectively, the expression of the proteins HOXA5, HOXA10, and HOXA11; these proteins' mRNAs exhibited significant binding with the miR-23a cluster miRNAs, and miRNA 3′-UTR reporter assays confirmed repression. Importantly, during periods correlating with development and differentiation of bone cells, we found an inverse pattern of expression between HoxA factors and members of the miR-23a cluster. HOXA5 and HOXA11 bound to ...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Tanner C. Godfrey, Benjamin J. Wildman, Marcio M. Beloti, Austin G. Kemper, Emanuela P. Ferraz, Bhaskar Roy, Mohammad Rehan, Lubana H. Afreen, Eddy Kim, Christopher J. Lengner, Quamarul Hassan Tags: Gene Regulation Source Type: research

The effects of CD14 and IL-27 on induction of endotoxin tolerance in human monocytes and macrophages [Cell Biology]
This study investigated the effects of IL-27 on the induction of endotoxin tolerance in models of human monocytes compared with macrophages. Our data demonstrate that IL-27 inhibits endotoxin tolerance by up-regulating cell surface TLR4 expression and soluble CD14 production to mediate stability of the surface LPS-TLR4-CD14 complex in THP-1 cells. In contrast, elevated basal expression of membrane-bound CD14 in phorbol 12-myristate 13-acetate (PMA)–THP-1 cells, primary monocytes, and primary macrophages may promote CD14-mediated endocytosis and be responsible for the preservation of an endotoxin-tolerized state in th...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Carlene Petes, Victoria Mintsopoulos, Renee L. Finnen, Bruce W. Banfield, Katrina Gee Tags: Immunology Source Type: research

The intracellular parasite Toxoplasma gondii harbors three druggable FNT-type formate and l-lactate transporters in the plasma membrane [Membrane Biology]
Toxoplasma gondii is a globally prevalent parasitic protist. It is well-known for its ability to infect almost all nucleated vertebrate cells, which is reflected by its unique metabolic architecture. Its fast-growing tachyzoite stage catabolizes glucose via glycolysis to yield l-lactate as a major by-product that must be exported from the cell to prevent toxicity; the underlying mechanism remains to be elucidated, however. Herein, we report three formate–nitrite transporter (FNT)–type monocarboxylate/proton symporters located in the plasma membrane of the T. gondii tachyzoite stage. We observed that all three p...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Holger Erler, Bingjian Ren, Nishith Gupta, Eric Beitz Tags: Microbiology Source Type: research

Functional and phylogenetic characterization of noncanonical vitamin B12-binding proteins in zebrafish suggests involvement in cobalamin transport [Molecular Bases of Disease]
In humans, transport of food-derived cobalamin (vitamin B12) from the digestive system into the bloodstream involves three paralogous proteins: transcobalamin (TC), haptocorrin (HC), and intrinsic factor (IF). Each of these proteins contains two domains, an α-domain and a β-domain, which together form a cleft in which cobalamin binds. Zebrafish (Danio rerio) are thought to possess only a single cobalamin transport protein, referred to as Tcn2, which is a transcobalamin homolog. Here, we used CRISPR/Cas9 mutagenesis to create null alleles of tcn2 in zebrafish. Fish homozygous for tcn2-null alleles were viable and...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Courtney R. Benoit, Abigail E. Stanton, Aileen C. Tartanian, Andrew R. Motzer, David M. McGaughey, Stephen R. Bond, Lawrence C. Brody Tags: Metabolism Source Type: research

Porin proteins have critical functions in mitochondrial phospholipid metabolism in yeast [Lipids]
Mitochondrial synthesis of cardiolipin (CL) and phosphatidylethanolamine requires the transport of their precursors, phosphatidic acid and phosphatidylserine, respectively, to the mitochondrial inner membrane. In yeast, the Ups1–Mdm35 and Ups2–Mdm35 complexes transfer phosphatidic acid and phosphatidylserine, respectively, between the mitochondrial outer and inner membranes. Moreover, a Ups1-independent CL accumulation pathway requires several mitochondrial proteins with unknown functions including Mdm31. Here, we identified a mitochondrial porin, Por1, as a protein that interacts with both Mdm31 and Mdm35 in b...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Non Miyata, Satoru Fujii, Osamu Kuge Tags: Cell Biology Source Type: research

Thumb domains of the three epithelial Na+ channel subunits have distinct functions [Protein Structure and Folding]
The epithelial Na+ channel (ENaC) possesses a large extracellular domain formed by a β-strand core enclosed by three peripheral α-helical subdomains, which have been dubbed thumb, finger, and knuckle. Here we asked whether the ENaC thumb domains play specific roles in channel function. To this end, we examined the characteristics of channels lacking a thumb domain in an individual ENaC subunit (α, β, or γ). Removing the γ subunit thumb domain had no effect on Na+ currents when expressed in Xenopus oocytes, but moderately reduced channel surface expression. In contrast, ENaCs lacking the &a...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Shaohu Sheng, Jingxin Chen, Anindit Mukherjee, Megan E. Yates, Teresa M. Buck, Jeffrey L. Brodsky, Michael A. Tolino, Rebecca P. Hughey, Thomas R. Kleyman Tags: Membrane Biology Source Type: research

K-Ras Lys-42 is crucial for its signaling, cell migration, and invasion [Signal Transduction]
Ras proteins participate in multiple signal cascades, regulating crucial cellular processes, including cell survival, proliferation, and differentiation. We have previously reported that Ras proteins are modified by sumoylation and that Lys-42 plays an important role in mediating the modification. In the current study, we further investigated the role of Lys-42 in regulating cellular activities of K-Ras. Inducible expression of K-RasV12 led to the activation of downstream components, including c-RAF, MEK1, and extracellular signal–regulated kinases (ERKs), whereas expression of K-RasV12/R42 mutant compromised the act...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Byeong Hyeok Choi, Mark R. Philips, Yuan Chen, Lou Lu, Wei Dai Tags: Cell Biology Source Type: research

The labile interactions of cyclic electron flow effector proteins [Membrane Biology]
The supramolecular organization of membrane proteins (MPs) is sensitive to environmental changes in photosynthetic organisms. Isolation of MP supercomplexes from the green algae Chlamydomonas reinhardtii, which are believed to contribute to cyclic electron flow (CEF) between the cytochrome b6f complex (Cyt-b6f) and photosystem I (PSI), proved difficult. We were unable to isolate a supercomplex containing both Cyt-b6f and PSI because in our hands, most of Cyt-b6f did not comigrate in sucrose density gradients, even upon using chemical cross-linkers or amphipol substitution of detergents. Assisted by independent affinity pur...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Felix Buchert, Marion Hamon, Philipp Gabelein, Martin Scholz, Michael Hippler, Francis–Andre Wollman Tags: Plant Biology Source Type: research

The small GTPase RAB28 is required for phagocytosis of cone outer segments by the murine retinal pigmented epithelium [Membrane Biology]
RAB28, a member of the RAS oncogene family, is a ubiquitous, farnesylated, small GTPase of unknown function present in photoreceptors and the retinal pigmented epithelium (RPE). Nonsense mutations of the human RAB28 gene cause recessive cone-rod dystrophy 18 (CRD18), characterized by macular hyperpigmentation, progressive loss of visual acuity, RPE atrophy, and severely attenuated cone and rod electroretinography (ERG) responses. In an attempt to elucidate the disease-causing mechanism, we generated Rab28−/− mice by deleting exon 3 and truncating RAB28 after exon 2. We found that Rab28−/− mice recap...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Guoxin Ying, Karsten Boldt, Marius Ueffing, Cecilia D. Gerstner, Jeanne M. Frederick, Wolfgang Baehr Tags: Molecular Bases of Disease Source Type: research

Functional and structural characterization of the chikungunya virus translational recoding signals [RNA]
Climate change and human globalization have spurred the rapid spread of mosquito-borne diseases to naïve populations. One such emerging virus of public health concern is chikungunya virus (CHIKV), a member of the Togaviridae family, genus Alphavirus. CHIKV pathogenesis is predominately characterized by acute febrile symptoms and severe arthralgia, which can persist in the host long after viral clearance. CHIKV has also been implicated in cases of acute encephalomyelitis, and its vertical transmission has been reported. Currently, no FDA-approved treatments exist for this virus. Recoding elements help expand the coding...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Joseph A. Kendra, Vivek M. Advani, Bin Chen, Joseph W. Briggs, Jinyi Zhu, Hannah J. Bress, Sushrut M. Pathy, Jonathan D. Dinman Tags: Protein Synthesis and Degradation Source Type: research

Dimerization interface of osteoprotegerin revealed by hydrogen-deuterium exchange mass spectrometry [Protein Structure and Folding]
Previous structural studies of osteoprotegerin (OPG), a crucial negative regulator of bone remodeling and osteoclastogenesis, were mostly limited to the N-terminal ligand-binding domains. It is now known that the three C-terminal domains of OPG also play essential roles in its function by mediating OPG dimerization, OPG–heparan sulfate (HS) interactions, and formation of the OPG–HS–receptor activator of nuclear factor κB ligand (RANKL) ternary complex. Employing hydrogen–deuterium exchange MS methods, here we investigated the structure of full-length OPG in complex with HS or RANKL in solution...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Yiming Xiao, Miaomiao Li, Rinzhi Larocque, Fuming Zhang, Anju Malhotra, Jianle Chen, Robert J. Linhardt, Lars Konermann, Ding Xu Tags: Glycobiology and Extracellular Matrices Source Type: research

Complex formation of sphingomyelin synthase 1 with glucosylceramide synthase increases sphingomyelin and decreases glucosylceramide levels [Enzymology]
Sphingolipids, including sphingomyelin (SM) and glucosylceramide (GlcCer), are generated by the addition of a polar head group to ceramide (Cer). Sphingomyelin synthase 1 (SMS1) and glucosylceramide synthase (GCS) are key enzymes that catalyze the conversion of Cer to SM and GlcCer, respectively. GlcCer synthesis has been postulated to occur mainly in cis-Golgi, and SM synthesis is thought to occur in medial/trans-Golgi; however, SMS1 and GCS are known to partially co-localize in cisternae, especially in medial/trans-Golgi. Here, we report that SMS1 and GCS can form a heteromeric complex, in which the N terminus of SMS1 an...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Yasuhiro Hayashi, Yoko Nemoto-Sasaki, Naoki Matsumoto, Kotaro Hama, Takashi Tanikawa, Saori Oka, Tadaaki Saeki, Tatsuya Kumasaka, Takanori Koizumi, Seisuke Arai, Ikuo Wada, Kazuaki Yokoyama, Takayuki Sugiura, Atsushi Yamashita Tags: Lipids Source Type: research

Characterization of Lhr-Core DNA helicase and manganese- dependent DNA nuclease components of a bacterial gene cluster encoding nucleic acid repair enzymes [Enzymology]
We report that P. putida Lhr-Core is an ssDNA-dependent ATPase/dATPase (Km, 0.37 mm ATP; kcat, 3.3 s−1), an ATP-dependent 3′-to-5′ single-stranded DNA translocase, and an ATP-dependent 3′-to-5′ helicase. Lhr-Core unwinds 3′-tailed duplexes in which the loading/tracking strand is DNA and the displaced strand is either DNA or RNA. We found that P. putida MPE is a manganese-dependent phosphodiesterase that releases p-nitrophenol from bis-p-nitrophenyl phosphate (kcat, 212 s−1) and p-nitrophenyl-5′-thymidylate (kcat, 34 s−1) but displays no detectable phosphomonoesterase ac...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Anam Ejaz, Stewart Shuman Tags: DNA and Chromosomes Source Type: research

Direct observation of conformational dynamics of the PH domain in phospholipases Cε and {beta} may contribute to subfamily-specific roles in regulation [Protein Structure and Folding]
Phospholipase C (PLC) enzymes produce second messengers that increase the intracellular Ca2+ concentration and activate protein kinase C (PKC). These enzymes also share a highly conserved arrangement of core domains. However, the contributions of the individual domains to regulation are poorly understood, particularly in isoforms lacking high-resolution information, such as PLCϵ. Here, we used small-angle X-ray scattering (SAXS), EM, and functional assays to gain insights into the molecular architecture of PLCϵ, revealing that its PH domain is conformationally dynamic and essential for activity. We further demonstrate th...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Elisabeth E. Garland-Kuntz, Frank S. Vago, Monita Sieng, Michelle Van Camp, Srinivas Chakravarthy, Arryn Blaine, Clairissa Corpstein, Wen Jiang, Angeline M. Lyon Tags: Signal Transduction Source Type: research

Redox regulation of type-I inositol trisphosphate receptors in intact mammalian cells [Cell Biology]
A sensitization of inositol 1,4,5-trisphosphate receptor (IP3R)–mediated Ca2+ release is associated with oxidative stress in multiple cell types. These effects are thought to be mediated by alterations in the redox state of critical thiols in the IP3R, but this has not been directly demonstrated in intact cells. Here, we utilized a combination of gel-shift assays with MPEG-maleimides and LC–MS/MS to monitor the redox state of recombinant IP3R1 expressed in HEK293 cells. We found that under basal conditions, ∼5 of the 60 cysteines are oxidized in IP3R1. Cell treatment with 50 μm thimerosal altered gel shi...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Suresh K. Joseph, Michael P. Young, Kamil Alzayady, David I. Yule, Mehboob Ali, David M. Booth, Gyorgy Haȷnoczky Tags: Signal Transduction Source Type: research

CARM1-mediated methylation of protein arginine methyltransferase 5 represses human {gamma}-globin gene expression in erythroleukemia cells [DNA and Chromosomes]
In this study, using MS analyses, we found that PRMT5 itself is methylated in human erythroleukemia Lys-562 cells. Biochemical assays revealed that coactivator-associated arginine methyltransferase 1 (CARM1) interacts directly with and methylates PRMT5 at Arg-505 both in vivo and in vitro. Substitutions at Arg-505 significantly reduced PRMT5's methyltransferase activity, decreased H4R3me2s enrichment at the γ-globin gene promoter, and increased the expression of the γ-globin gene in Lys-562 cells. Moreover, CARM1 knockdown consistently reduced PRMT5 activity and activated γ-globin gene expression. Importa...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Min Nie, Yadong Wang, Chan Guo, Xinyu Li, Ying Wang, Yexuan Deng, Bing Yao, Tao Gui, Chi Ma, Ming Liu, Panxue Wang, Ruoyun Wang, Renxiang Tan, Ming Fang, Bing Chen, Yinghong He, David C. S. Huang, Junyi Ju, Quan Zhao Tags: Gene Regulation Source Type: research

An ankyrin-binding motif regulates nuclear levels of L1-type neuroglian and expression of the oncogene Myc in Drosophila neurons [Neurobiology]
L1 cell adhesion molecule (L1CAM) is well-known for its importance in nervous system development and cancer progression. In addition to its role as a plasma membrane protein in cytoskeletal organization, recent in vitro studies have revealed that both transmembrane and cytosolic fragments of proteolytically cleaved vertebrate L1CAM translocate to the nucleus. In vitro studies indicate that nuclear L1CAM affects genes with functions in DNA post-replication repair, cell cycle control, and cell migration and differentiation, but its in vivo role and how its nuclear levels are regulated is less well-understood. Here, we report...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Priyanka P. Kakad, Tyrone Penserga, Blake P. Davis, Brittany Henry, Jana Boerner, Anna Riso, Jan Pielage, Tanja A. Godenschwege Tags: Cell Biology Source Type: research

OSBP-related protein 4L promotes phospholipase C{beta}3 translocation from the nucleus to the plasma membrane in Jurkat T-cells [Signal Transduction]
This study reveals detailed mechanistic insight into the role of ORP4L in PLCβ3 redistribution from storage within the nucleus to the plasma membrane via RAN activation and interaction with VAPA in Jurkat T-cells. (Source: Journal of Biological Chemistry)
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Guoping Pan, Xiuye Cao, Bo Liu, Chaowen Li, Dan Li, Jie Zheng, Chaofeng Lai, Vesa M. Olkkonen, Wenbin Zhong, Daoguang Yan Tags: Cell Biology Source Type: research

Mechanism of action of the viral chemokine-binding protein E163 from ectromelia virus [Microbiology]
We report the identification of the GAG-binding regions in E163 and the generation of mutant forms deficient of GAG binding. Chemokine binding assays show that some of the E163 GAG-binding sites are also involved in the interaction with chemokines. By using recombinant GAG-binding mutant forms we demonstrate that E163 prevents the interaction of chemokines with cell-surface GAGs, providing mechanisms for the immunomodulatory activity of the viral chemokine-binding protein E163. (Source: Journal of Biological Chemistry)
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Haleh Heidarieh, Antonio Alcami Tags: Immunology Source Type: research

Calcium-sensitive pyruvate dehydrogenase phosphatase is required for energy metabolism, growth, differentiation, and infectivity of Trypanosoma cruzi [Bioenergetics]
In vertebrate cells, mitochondrial Ca2+ uptake by the mitochondrial calcium uniporter (MCU) leads to Ca2+-mediated stimulation of an intramitochondrial pyruvate dehydrogenase phosphatase (PDP). This enzyme dephosphorylates serine residues in the E1α subunit of pyruvate dehydrogenase (PDH), thereby activating PDH and resulting in increased ATP production. Although a phosphorylation/dephosphorylation cycle for the E1α subunit of PDH from nonvertebrate organisms has been described, the Ca2+-mediated PDP activation has not been studied. In this work, we investigated the Ca2+ sensitivity of two recombinant PDPs from...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Noelia Lander, Miguel A. Chiurillo, Mayara S. Bertolini, Melissa Storey, Anibal E. Vercesi, Roberto Docampo Tags: Microbiology Source Type: research

ROS-induced HSP70 promotes cytoplasmic translocation of high-mobility group box 1b and stimulates antiviral autophagy in grass carp kidney cells [Cell Biology]
In this study, we found that both grass carp reovirus (GCRV) infection and hydrogen peroxide (H2O2) treatment induced the accumulation of reactive oxygen species (ROS) in C. idella kidney cells and stimulate autophagy. Suppressing ROS accumulation with N-acetyl-l-cysteine significantly inhibited GCRV-induced autophagy activation and enhanced GCRV replication. Although ROS-induced autophagy, in turn, restricted GCRV replication, further investigation revealed that the multifunctional cellular protein high-mobility group box 1b (HMGB1b) serves as a heat shock protein 70 (HSP70)–dependent, pro-autophagic protein in gras...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Youliang Rao, Quanyuan Wan, Hang Su, Xun Xiao, Zhiwei Liao, Jianfei Ji, Chunrong Yang, Li Lin, Jianguo Su Tags: Immunology Source Type: research

Identification, functional characterization, and crystal structure determination of bacterial levoglucosan dehydrogenase [Protein Structure and Folding]
Levoglucosan is the 1,6-anhydrosugar of d-glucose formed by pyrolysis of glucans and is found in the environment and industrial waste. Two types of microbial levoglucosan metabolic pathways are known. Although the eukaryotic pathway involving levoglucosan kinase has been well-studied, the bacterial pathway involving levoglucosan dehydrogenase (LGDH) has not been well-investigated. Here, we identified and cloned the lgdh gene from the bacterium Pseudarthrobacter phenanthrenivorans and characterized the recombinant protein. The enzyme exhibited high substrate specificity toward levoglucosan and NAD+ for the oxidative reactio...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Masayuki Sugiura, Moe Nakahara, Chihaya Yamada, Takatoshi Arakawa, Motomitsu Kitaoka, Shinya Fushinobu Tags: Enzymology Source Type: research

The structure of the deubiquitinase USP15 reveals a misaligned catalytic triad and an open ubiquitin-binding channel [Enzymology]
Ubiquitin-specific protease 15 (USP15) regulates important cellular processes, including transforming growth factor β (TGF-β) signaling, mitophagy, mRNA processing, and innate immune responses; however, structural information on USP15's catalytic domain is currently unavailable. Here, we determined crystal structures of the USP15 catalytic core domain, revealing a canonical USP fold, including a finger, palm, and thumb region. Unlike for the structure of paralog USP4, the catalytic triad is in an inactive configuration with the catalytic cysteine ∼10 Å apart from the catalytic histidine. This conformati...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Stephanie J. Ward, Hayley E. Gratton, Peni Indrayudha, Camille Michavila, Rishov Mukhopadhyay, Sigrun K. Maurer, Simon G. Caulton, Jonas Emsley, Ingrid Dreveny Tags: Protein Structure and Folding Source Type: research

Structural and spectroscopic analyses of the sporulation killing factor biosynthetic enzyme SkfB, a bacterial AdoMet radical sactisynthase [Protein Structure and Folding]
Sactipeptides are a subclass of ribosomally synthesized and post-translationally modified peptides (RiPPs). They contain a unique thioether bond, referred to as a sactionine linkage, between the sulfur atom of a cysteine residue and the α-carbon of an acceptor residue. These linkages are formed via radical chemistry and are essential for the spermicidal, antifungal, and antibacterial properties of sactipeptides. Enzymes that form these linkages, called sactisynthases, are AdoMet radical enzymes in the SPASM/Twitch subgroup whose structures are incompletely characterized. Here, we present the X-ray crystal structure t...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Tsehai A. J. Grell, William M. Kincannon, Nathan A. Bruender, Elizabeth J. Blaesi, Carsten Krebs, Vahe Bandarian, Catherine L. Drennan Tags: Enzymology Source Type: research

Structural disorder in four-repeat Tau fibrils reveals a new mechanism for barriers to cross-seeding of Tau isoforms [Molecular Bases of Disease]
The intracellular deposition of fibrils composed of the microtubule-associated protein Tau is a characteristic feature of Alzheimer's disease (AD) and other fatal neurodegenerative disorders collectively known as tauopathies. Short Tau fibrils spread intracerebrally through transfer between interconnected neurons. Once taken up by a recipient cell, Tau fibrils recruit Tau monomers onto their ends. Based on the number of microtubule-binding repeats, there are two distinct groups of Tau isoforms: three-repeat (3R) Tau and four-repeat (4R) Tau. In AD, all Tau isoforms are deposited, whereas in other tauopathies, only 3R or 4R...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Hilary A. Weismiller, Rachel Murphy, Guanghong Wei, Buyong Ma, Ruth Nussinov, Martin Margittai Tags: Protein Structure and Folding Source Type: research

The scaffolding protein ZO-1 coordinates actomyosin and epithelial apical specializations in vitro and in vivo [Cell Biology]
Polarized epithelia assemble into sheets that compartmentalize organs and generate tissue barriers by integrating apical surfaces into a single, unified structure. This tissue organization is shared across organs, species, and developmental stages. The processes that regulate development and maintenance of apical epithelial surfaces are, however, undefined. Here, using an intestinal epithelial-specific knockout (KO) mouse and cultured epithelial cells, we show that the tight junction scaffolding protein zonula occludens-1 (ZO-1) is essential for development of unified apical surfaces in vivo and in vitro. We found that U5 ...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Matthew A. Odenwald, Wangsun Choi, Wei-Ting Kuo, Gurminder Singh, Anne Sailer, Yitang Wang, Le Shen, Alan S. Fanning, Jerrold R. Turner Tags: Editors ' Picks Source Type: research

Role of phospholipid synthesis in the development and differentiation of malaria parasites in the blood [Microbiology]
The life cycle of malaria parasites in both their mammalian host and mosquito vector consists of multiple developmental stages that ensure proper replication and progeny survival. The transition between these stages is fueled by nutrients scavenged from the host and fed into specialized metabolic pathways of the parasite. One such pathway is used by Plasmodium falciparum, which causes the most severe form of human malaria, to synthesize its major phospholipids, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Much is known about the enzymes involved in the synthesis of these phospholipids, and recent ...
Source: Journal of Biological Chemistry - November 9, 2018 Category: Chemistry Authors: Nicole Kilian, Jae-Yeon Choi, Dennis R. Voelker, Choukri Ben Mamoun Tags: Minireviews Source Type: research

A peptide delivery system sneaks CRISPR into cells [Gene Regulation]
The CRISPR-Cas9 system has developed into a powerful platform for genome editing in various types of cells and tissues with single-nucleotide precision, but limited delivery options hamper its application in real-world settings. A new study by Shen et al. describes the use of an amphipathic peptide to deliver Cas9/sgRNA ribonucleoprotein complexes, leading to the disruption of GFP genes in cells and mice. Disruption of the Nrip1 gene in isolated pre-adipocytes led to a “browning” phenotype, pointing to new options in the fight against diabetes and obesity. (Source: Journal of Biological Chemistry)
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Xingang Guan, Zhimin Luo, Wujin Sun Tags: Editors ' Picks Highlights Source Type: research

CRISPR-delivery particles targeting nuclear receptor-interacting protein 1 (Nrip1) in adipose cells to enhance energy expenditure [Methods and Resources]
RNA-guided, engineered nucleases derived from the prokaryotic adaptive immune system CRISPR-Cas represent a powerful platform for gene deletion and editing. When used as a therapeutic approach, direct delivery of Cas9 protein and single-guide RNA (sgRNA) could circumvent the safety issues associated with plasmid delivery and therefore represents an attractive tool for precision genome engineering. Gene deletion or editing in adipose tissue to enhance its energy expenditure, fatty acid oxidation, and secretion of bioactive factors through a “browning” process presents a potential therapeutic strategy to alleviat...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Yuefei Shen, Jessica L. Cohen, Sarah M. Nicoloro, Mark Kelly, Batuhan Yenilmez, Felipe Henriques, Emmanouela Tsagkaraki, Yvonne J. K. Edwards, Xiaodi Hu, Randall H. Friedline, Jason K. Kim, Michael P. Czech Tags: Editors ' Picks Source Type: research

Insulin-like growth factor-1 acts as a zeitgeber on hypothalamic circadian clock gene expression via glycogen synthase kinase-3{beta} signaling [Cell Biology]
Brain and muscle ARNT-like protein-1 (BMAL-1) is an important component of the cellular circadian clock. Proteins such as epidermal (EGF) or nerve growth factor (NGF) affect the cellular clock via extracellular signal–regulated kinases-1/2 (ERK-1/2) in NIH3T3 or neuronal stem cells, but no such data are available for the insulin-like growth factor-1 (IGF-1). The hypothalamus expresses receptors for all three growth factors, acts as a central circadian pacemaker, and releases hormones in a circadian fashion. However, little is known about growth factor–induced modulation of clock gene activity in hypothalamic ce...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Andreas Breit, Laura Miek, Johann Schredelseker, Mirjam Geibel, Martha Merrow, Thomas Gudermann Tags: Signal Transduction Source Type: research

Quaternary structure of the small amino acid transporter OprG from Pseudomonas aeruginosa [Membrane Biology]
Pseudomonas aeruginosa is an opportunistic human pathogen that causes nosocomial infections. The P. aeruginosa outer membrane contains specific porins that enable substrate uptake, with the outer membrane protein OprG facilitating transport of small, uncharged amino acids. However, the pore size of an eight-stranded β-barrel monomer of OprG is too narrow to accommodate even the smallest transported amino acid, glycine, raising the question of how OprG facilitates amino acid uptake. Pro-92 of OprG is critically important for amino acid transport, with a P92A substitution inhibiting transport and the NMR structure of th...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Raghavendar Reddy Sanganna Gari, Patrick Seelheim, Brendan Marsh, Volker Kiessling, Carl E. Creutz, Lukas K. Tamm Tags: Membrane Biology Source Type: research

Helicobacter pylori-binding nonacid glycosphingolipids in the human stomach [Microbiology]
Helicobacter pylori has a number of well-characterized carbohydrate-binding adhesins (BabA, SabA, and LabA) that promote adhesion to the gastric mucosa. In contrast, information on the glycoconjugates present in the human stomach remains unavailable. Here, we used MS and binding of carbohydrate-recognizing ligands to characterize the glycosphingolipids of three human stomachs from individuals with different blood group phenotypes (O(Rh−)P, A(Rh+)P, and A(Rh+)p), focusing on compounds recognized by H. pylori. We observed a high degree of structural complexity, and the composition of glycosphingolipids differed among i...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Chunsheng Jin, Angela Barone, Thomas Boren, Susann Teneberg Tags: Glycobiology and Extracellular Matrices Source Type: research

Discovery and characterization of conserved binding of eIF4E 1 (CBE1), a eukaryotic translation initiation factor 4E-binding plant protein [Protein Synthesis and Degradation]
In many eukaryotes, translation initiation is regulated by proteins that bind to the mRNA cap–binding protein eukaryotic translation initiation factor 4E (eIF4E). These proteins commonly prevent association of eIF4E with eIF4G or form repressive messenger ribonucleoproteins that exclude the translation machinery. Such gene-regulatory mechanisms in plants, and even the presence of eIF4E-interacting proteins other than eIF4G (and the plant-specific isoform eIFiso4G, which binds eIFiso4E), are unknown. Here, we report the discovery of a plant-specific protein, conserved binding of eIF4E 1 (CBE1). We found that CBE1 has ...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Ryan M. Patrick, Jessica C. H. Lee, Jade R. J. Teetsel, Soo-Hyun Yang, Grace S. Choy, Karen S. Browning Tags: Protein Synthesis and Degradation Source Type: research

c-Jun N-terminal kinase (JNK)-mediated induction of mSin1 expression and mTORC2 activation in mesenchymal cells during fibrosis [Cell Biology]
Mammalian target of rapamycin complex 2 (mTORC2) has been shown to regulate mTORC1/4E-BP1/eIF4E signaling and collagen I expression in mesenchymal cells (MCs) during fibrotic activation. Here we investigated the regulation of the mTORC2 binding partner mammalian stress-activated protein kinase–interacting protein 1 (mSin1) in MCs derived from human lung allografts and identified a novel role for mSin1 during fibrosis. mSin1 was identified as a common downstream target of key fibrotic pathways, and its expression was increased in MCs in response to pro-fibrotic mediators: lysophosphatidic acid (LPA), transforming grow...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Natalie M. Walker, Serina M. Mazzoni, Ragini Vittal, Diane C. Fingar, Vibha N. Lama Tags: Cell Biology Source Type: research

Fibroblast growth factor receptor 5 (FGFR5) is a co-receptor for FGFR1 that is up-regulated in beta-cells by cytokine-induced inflammation [Metabolism]
Fibroblast growth factor receptor-1 (FGFR1) activity at the plasma membrane is tightly controlled by the availability of co-receptors and competing receptor isoforms. We have previously shown that FGFR1 activity in pancreatic beta-cells modulates a wide range of processes, including lipid metabolism, insulin processing, and cell survival. More recently, we have revealed that co-expression of FGFR5, a receptor isoform that lacks a tyrosine-kinase domain, influences FGFR1 responses. We therefore hypothesized that FGFR5 is a co-receptor to FGFR1 that modulates responses to ligands by forming a receptor heterocomplex with FGFR...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Romario Regeenes, Pamuditha N. Silva, Huntley H. Chang, Edith J. Arany, Andrey I. Shukalyuk, Julie Audet, Dawn M. Kilkenny, Jonathan V. Rocheleau Tags: Signal Transduction Source Type: research

Mitochondria-derived ROS activate AMP-activated protein kinase (AMPK) indirectly [Signal Transduction]
Mitochondrial reactive oxygen species (ROS) production is a tightly regulated redox signal that transmits information from the organelle to the cell. Other mitochondrial signals, such as ATP, are sensed by enzymes, including the key metabolic sensor and regulator, AMP-activated protein kinase (AMPK). AMPK responds to the cellular ATP/AMP and ATP/ADP ratios by matching mitochondrial ATP production to demand. Previous reports proposed that AMPK activity also responds to ROS, by ROS acting on redox-sensitive cysteine residues (Cys-299/Cys-304) on the AMPK α subunit. This suggests an appealing model in which mitochondria...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Elizabeth C. Hinchy, Anja V. Gruszczyk, Robin Willows, Naveenan Navaratnam, Andrew R. Hall, Georgina Bates, Thomas P. Bright, Thomas Krieg, David Carling, Michael P. Murphy Tags: Bioenergetics Source Type: research

InhA, the enoyl-thioester reductase from Mycobacterium tuberculosis forms a covalent adduct during catalysis [Enzymology]
The enoyl-thioester reductase InhA catalyzes an essential step in fatty acid biosynthesis of Mycobacterium tuberculosis and is a key target of antituberculosis drugs to combat multidrug-resistant M. tuberculosis strains. This has prompted intense interest in the mechanism and intermediates of the InhA reaction. Here, using enzyme mutagenesis, NMR, stopped-flow spectroscopy, and LC–MS, we found that the NADH cofactor and the CoA thioester substrate form a covalent adduct during the InhA catalytic cycle. We used the isolated adduct as a molecular probe to directly access the second half-reaction of the catalytic cycle ...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Bastian Vogeli, Raoul G. Rosenthal, Gabriele M. M. Stoffel, Tristan Wagner, Patrick Kiefer, Nina Socorro Cortina, Seigo Shima, Tobias J. Erb Tags: Enzymology Source Type: research

Plasma membrane profiling during enterohemorrhagic E. coli infection reveals that the metalloprotease StcE cleaves CD55 from host epithelial surfaces [Genomics and Proteomics]
Enterohemorrhagic Escherichia coli (EHEC) is one of several E. coli pathotypes that infect the intestinal tract and cause disease. Formation of the characteristic attaching and effacing lesion on the surface of infected cells causes significant remodeling of the host cell surface; however, limited information is available about changes at the protein level. Here we employed plasma membrane profiling, a quantitative cell-surface proteomics technique, to identify host proteins whose cell-surface levels are altered during infection. Using this method, we quantified more than 1100 proteins, 280 of which showed altered cell-sur...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: R. Christopher D. Furniss, Wen Wen Low, Despoina A. I. Mavridou, Laura F. Dagley, Andrew I. Webb, Edward W. Tate, Abigail Clements Tags: Microbiology Source Type: research

Two distinct conformations of factor H regulate discrete complement-binding functions in the fluid phase and at cell surfaces [Protein Structure and Folding]
Factor H (FH) is the major regulator of C3b in the alternative pathway of the complement system in immunity. FH comprises 20 short complement regulator (SCR) domains, including eight glycans, and its Y402H polymorphism predisposes those who carry it to age-related macular degeneration. To better understand FH complement binding and self-association, we have studied the solution structures of both the His-402 and Tyr-402 FH allotypes. Analytical ultracentrifugation revealed that up to 12% of both FH allotypes self-associate, and this was confirmed by small-angle X-ray scattering (SAXS), MS, and surface plasmon resonance ana...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Amy J. Osborne, Ruodan Nan, Ami Miller, Jayesh S. Bhatt, Jayesh Gor, Stephen J. Perkins Tags: Immunology Source Type: research

The long noncoding RNA GAS8-AS1 suppresses hepatocarcinogenesis by epigenetically activating the tumor suppressor GAS8 [Molecular Bases of Disease]
In this study, we report that both GAS8-AS1 and its host gene GAS8 act as HCC tumor suppressors. We found that expression of GAS8-AS1 or GAS8 is significantly decreased in HCC tissues and is associated with a poor prognosis among HCC patients. Interestingly, lncRNA GAS8-AS1 could promote GAS8 transcription. We detected a CpG island in the GAS8 promoter, but lncRNA GAS8-AS1 did not affect DNA methylation at this GAS8 promoter site. Moreover, we identified two GAS8-AS1–interacting proteins, mixed-lineage leukemia 1 (MLL1), a histone 3 Lys-4 (H3K4) methyltransferase, and its partner WD-40 repeat protein 5 (WDR5). RNA pu...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Wenting Pan, Nasha Zhang, Wenjuan Liu, Jibing Liu, Liqing Zhou, Yang Liu, Ming Yang Tags: RNA Source Type: research

Altered oligomeric states in pathogenic ALS2 variants associated with juvenile motor neuron diseases cause loss of ALS2-mediated endosomal function [Protein Structure and Folding]
Familial amyotrophic lateral sclerosis type 2 (ALS2) is a juvenile autosomal recessive motor neuron disease caused by the mutations in the ALS2 gene. The ALS2 gene product, ALS2/alsin, forms a homophilic oligomer and acts as a guanine nucleotide–exchange factor (GEF) for the small GTPase Rab5. This oligomerization is crucial for both Rab5 activation and ALS2-mediated endosome fusion and maturation in cells. Recently, we have shown that pathogenic missense ALS2 mutants retaining the Rab5 GEF activity fail to properly localize to endosomes via Rac1-stimulated macropinocytosis. However, the molecular mechanisms underlyi...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Kai Sato, Asako Otomo, Mahoko Takahashi Ueda, Yui Hiratsuka, Kyoko Suzuki-Utsunomiya, Junya Sugiyama, Shuji Murakoshi, Shun Mitsui, Suzuka Ono, So Nakagawa, Hui-Fang Shang, Shinji Hadano Tags: Molecular Bases of Disease Source Type: research

The TEA domain family transcription factor TEAD4 represses murine adipogenesis by recruiting the cofactors VGLL4 and CtBP2 into a transcriptional complex [Signal Transduction]
The Hippo signaling pathway is known to play an important role in multiple physiological processes, including adipogenesis. However, whether the downstream components of the Hippo pathway are involved in adipogenesis remains unknown. Here we demonstrate that the TEA domain family (TEAD) transcription factors are essential for adipogenesis in murine 3T3-L1 preadipocytes. Knockdown of TEAD1–4 stimulated adipogenesis and increased the expression of adipocyte markers in these cells. Interestingly, we found that the TEAD4 knockdown–mediated adipogenesis proceeded in a Yes-associated protein (YAP)/TAZ (Wwtr1)–i...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Wenxiang Zhang, Jinjin Xu, Jinhui Li, Tong Guo, Dan Jiang, Xue Feng, Xueyan Ma, Lingli He, Wenqing Wu, Mengxin Yin, Ling Ge, Zuoyun Wang, Margaret S. Ho, Yun Zhao, Zhaoliang Fei, Lei Zhang Tags: Cell Biology Source Type: research

A single residue switch reveals principles of antibody domain integrity [Molecular Biophysics]
Despite their importance for antibody architecture and design, the principles governing antibody domain stability are still not understood in sufficient detail. Here, to address this question, we chose a domain from the invariant part of IgG, the CH2 domain. We found that compared with other Ig domains, the isolated CH2 domain is a surprisingly unstable monomer, exhibiting a melting temperature of ∼44 °C. We further show that the presence of an additional C-terminal lysine in a CH2 variant substantially increases the melting temperature by ∼14 °C relative to CH2 WT. To explore the molecular mechanism of thi...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Benedikt Weber, Matthias J. Brandl, Maria Daniela Pulido Cendales, Carolin Berner, Teȷaswini Pradhan, Gina Maria Feind, Martin Zacharias, Bernd Reif, Johannes Buchner Tags: Protein Structure and Folding Source Type: research

In vivo cross-linking supports a head-to-tail mechanism for regulation of the plant plasma membrane P-type H+-ATPase [Membrane Biology]
In this study, we used in vivo cross-linking experiments with a photoreactive unnatural amino acid, p-benzoylphenylalanine, and tandem MS to obtain direct evidence that the C-terminal regulatory domain interacts with amino acids located within the N-terminal actuator domain. Our observations are consistent with a mechanism in which intermolecular, rather than intramolecular, interactions are involved. Our model invokes a “head-to-tail” organization of ATPase monomers in which the C-terminal domain of one ATPase molecule interacts with the actuator domain of another ATPase molecule. This model serves to explain ...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Thao T. Nguyen, Grzegorz Sabat, Michael R. Sussman Tags: Plant Biology Source Type: research

Slow activation of fast mitochondrial Ca2+ uptake by cytosolic Ca2+ [Cell Biology]
Mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniporter (MCU) is a tightly controlled process that sustains cell functions mainly by fine-tuning oxidative metabolism to cellular needs. The kinetics of Ca2+ fluxes across the mitochondrial membranes have been studied both in vitro and in vivo for many years, and the discovery of the molecular components of the MCU has further clarified that this Ca2+ uptake mechanism is based on a complex system subject to elaborate layers of controls. Alterations in the speed or capacity of the in-and-out pathways can have detrimental consequences for both the organelle and the c...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Emy Basso, Giulia Rigotto, Andres E. Zucchetti, Tullio Pozzan Tags: Bioenergetics Source Type: research

Archaic and alternative chaperones preserve pilin folding energy by providing incomplete structural information [Microbiology]
Adhesive pili are external component of fibrous adhesive organelles and help bacteria attach to biotic or abiotic surfaces. The biogenesis of adhesive pili via the chaperone-usher pathway (CUP) is independent of external energy sources. In the classical CUP, chaperones transport assembly-competent pilins in a folded but expanded conformation. During donor-strand exchange, pilins subsequently collapse, producing a tightly packed hydrophobic core and releasing the necessary free energy to drive fiber formation. Here, we show that pilus biogenesis in non-classical, archaic, and alternative CUPs uses a different source of conf...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Natalia Pakharukova, Sophie McKenna, Minna Tuittila, Sari Paavilainen, Henri Malmi, Yingqi Xu, Olena Parilova, Steve Matthews, Anton V. Zavialov Tags: Protein Structure and Folding Source Type: research

A DNA nick at Ku-blocked double-strand break ends serves as an entry site for exonuclease 1 (Exo1) or Sgs1-Dna2 in long-range DNA end resection [DNA and Chromosomes]
The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is initiated by nucleolytic resection of the DNA break ends. The current model, being based primarily on genetic analyses in Saccharomyces cerevisiae and companion biochemical reconstitution studies, posits that end resection proceeds in two distinct stages. Specifically, the initiation of resection is mediated by the nuclease activity of the Mre11–Rad50–Xrs2 (MRX) complex in conjunction with its cofactor Sae2, and long-range resection is carried out by exonuclease 1 (Exo1) or the Sgs1–Top3–Rmi1–Dna2 ensemble. Using...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Weibin Wang, James M. Daley, Youngho Kwon, Xiaoyu Xue, Danielle S. Krasner, Adam S. Miller, Kevin A. Nguyen, Elizabeth A. Williamson, Eun Yong Shim, Sang Eun Lee, Robert Hromas, Patrick Sung Tags: DNA and Chromosomes Source Type: research

Interaction mapping of the Sec61 translocon identifies two Sec61{alpha} regions interacting with hydrophobic segments in translocating chains [Cell Biology]
Many proteins in organelles of the secretory pathway, as well as secretory proteins, are translocated across and inserted into the endoplasmic reticulum membrane by the Sec61 translocon, a protein-conducting channel. The channel consists of 10 transmembrane (TM) segments of the Sec61α subunit and possesses an opening between TM2b and TM7, termed the lateral gate. Structural and biochemical analyses of complexes of Sec61 and its ortholog SecY have revealed that the lateral gate is the exit for signal sequences and TM segments of translocating polypeptides to the lipid bilayer and also involved in the recognition of su...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Yuichiro Kida, Masao Sakaguchi Tags: Membrane Biology Source Type: research

Molecular architecture of G-quadruplex structures generated on duplex Rif1-binding sequences [DNA and Chromosomes]
G-quadruplexes (G4s) are four-stranded DNA structures comprising stacks of four guanines, are prevalent in genomes, and have diverse biological functions in various chromosomal structures. A conserved protein, Rap1-interacting factor 1 (Rif1) from fission yeast (Schizosaccharomyces pombe), binds to Rif1-binding sequence (Rif1BS) and regulates DNA replication timing. Rif1BS is characterized by the presence of multiple G-tracts, often on both strands, and their unusual spacing. Although previous studies have suggested generation of G4-like structures on duplex Rif1BS, its precise molecular architecture remains unknown. Using...
Source: Journal of Biological Chemistry - November 2, 2018 Category: Chemistry Authors: Hisao Masai, Naoko Kakusho, Rino Fukatsu, Yue Ma, Keisuke Iida, Yutaka Kanoh, Kazuo Nagasawa Tags: DNA and Chromosomes Source Type: research