|Protein Name||78 kDa glucose-regulated protein|
|Ref Sequence Id||NP_001068616.1|
|Amino Acid Lenth||655|
|Protein Existence Status||Reviewed: Experimental evidence at transcript level|
|Protein Function||immunoglobulin heavy chain binding protein1 and as the glucose regulated protein; ER-located member of the family of HSP70 molecular chaperones; binds transiently to newly-synthesized proteins in the ER and more permanently to misfolded, underglycosylated or unassembled proteins whose transport from the ER is blocked; assists the folding and assembly of newly-synthesized proteins by recognising unfolded polypeptides and, by inhibiting intra- or intermolecular aggregation, maintaining them in a state competent for subsequent folding and oligomerisation; maintain the permeability barrier of the ER membrane by sealing the lumenal end of the translocon pore before and early in translocation; required during ara cell mating for the stage of karyogamy that involves fusion of the nuclear membranes of Saccharomyces cerevisiae|
|Biochemical Properties||BiP does not interact with native polypeptides; two major domains, an N-terminal domain that contains the ATPase catalytic site and a C-terminal substrate bind- ing domain; domains communicate to regulate the affinity and duration of poly.peptide binding; In vitro, BiP can interact with short synthetic peptides whose binding stimulates its ATPase activity and alters its oligomeric state; interacts with sequences normally located in the interior of a fully-folded protein; presence of a heptameric motif with a bulky aromatic or hydrophobic residue most frequently tryptophan, phenylalanine or leucine, but also methionine and isoleucine.|
|Significance in milk||required for mammary gland development; contributes to the regulation of Cripto signaling in mammary stem cells; . Grp78 heterozygosity impeded transgene-induced mammary tumor development, with the tumors showing reduced proliferation, increased apoptosis, and dramatic reduction of tumor angiogenesis|
|PTMs||mammalian BiP exists in interconvertible monomeric and oligomeric forms and can be post-translationally modified by phosphorylation and by ADP ribosylation|
|Significance of PTMs||important in regulating the synthesis and polypeptide binding activity of the molecule; conditions that increase the levels of unfolded polypeptides in the ER lumen cause a decrease in the extent of modification of BiP and an increase in the proportion of monomeric species; post-translational modification of BiP appears to provide a storage pool of BiP that can be recruited back to the active form in response to need|
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