ISG'ylation increases stability of numerous proteins including Stat1, which prevents premature termination of immune response in LPS-stimulated microglia

Publication date: January 2018 Source:Neurochemistry International, Volume 112 Author(s): Piotr Przanowski, Stefan Loska, Dominik Cysewski, Michal Dabrowski, Bozena Kaminska Microglia are myeloid cells in the central nervous system which maintain homeostasis and contribute to repair, but instigate neuroinflammation when are activated by infection, trauma or neurological diseases. Initiation of acute inflammatory responses could be mimicked in vitro by stimulation of microglial cultures with lipopolysaccharide (LPS). We have previously demonstrated Stat-dependent induction of the Uba7 mRNA expression in LPS stimulated microglia. Uba7 is an E1 enzyme crucial for posttranslational protein modifications. ISG'ylation is a process in which ISG15 is covalently attached to lysines of target proteins via the sequential action of three enzymes: the E1-activating enzyme UbE1L (UBA7), the E2-conjugating enzyme UBCH8, and E3 ligase HERC5. Here we use quantitative labeled-free mass spectrometry and gene silencing to determine the role of ISG'ylation in LPS-stimulated microglia. We found the increased mRNA levels of Isg15, Uba7, Ube2l6, Herc6 and profound ISG'ylation in inflammatory microglia. Silencing of Uba7 in BV2 microglial cells results in a profound decrease in the level of hundreds proteins as measured by mass spectrometry. There is statistically significant intersection of Uba7-dependent proteins in LPS-stimulated microglia and three datasets of ISG'ylated proteins reported...
Source: Neurochemistry International - Category: Neuroscience Source Type: research