75 kDa glucose-regulated protein (GRP75) is a novel molecular signature for heat stress response in avian species.

75 kDa glucose-regulated protein (GRP75) is a novel molecular signature for heat stress response in avian species. Am J Physiol Cell Physiol. 2019 Dec 04;: Authors: Dhamad AE, Greene E, Sales M, Nguyen P, Beer L, Liyanage R, Dridi S Abstract GRP75 was first characterized in mammals as an HSP70 family stress chaperone based on its sequence homology. Extensive studies in mammals showed that GRP75 is induced by various stressors such as glucose deprivation, oxidative stress, and hypoxia, although it remained unresponsive to the heat shock. Such investigations are scarce in avian (non-mammalian) species. We identified here chicken GRP75 by using immunoprecipitation assay integrated with LC-MS/MS, and found that its amino acid sequence is conserved with high homology (52.5%) to HSP70 family. Bioinformatics and 3D-structure prediction indicate that, like most HSPs, chicken GRP75 has two principal domains (the N-terminal ATPase and C-terminal region). Immunofluorescence staining shows that GRP75 is predominantly localized in the avian myoblast and hepatocyte mitochondria. Heat stress exposure upregulates GRP75 expression in a species-, genotype-, and tissue-specific manner. Overexpression of GRP75 reduces avian cell viability and blockade of GRP75 by its small molecular inhibitor, MKT-077, rescues avian cell viability during heat stress. Taken together, this is the first evidence showing that chicken GRP75, unlike its mammalian orthologue, ...
Source: Am J Physiol Cell Ph... - Category: Cytology Authors: Tags: Am J Physiol Cell Physiol Source Type: research