FEATURES

FAMILY

DESCRIPTION

Also known as BIP_CRIGR, HSPA5, GRP78. Endoplasmic reticulum chaperone that plays a key role in protein folding and quality control in the endoplasmic reticulum lumen (By similarity). Involved in the correct folding of proteins and degradation of misfolded proteins via its interaction with DNAJC10/ERdj5, probably to facilitate the release of DNAJC10/ERdj5 from its substrate (By similarity). Acts as a key repressor of the ERN1/IRE1-mediated unfolded protein response (UPR) (PubMed:29198525). In the unstressed endoplasmic reticulum, recruited by DNAJB9/ERdj4 to the luminal region of ERN1/IRE1, leading to disrupt the dimerization of ERN1/IRE1, thereby inactivating ERN1/IRE1 (PubMed:29198525). Accumulation of misfolded protein in the endoplasmic reticulum causes release of HSPA5/BiP from ERN1/IRE1, allowing homodimerization and subsequent activation of ERN1/IRE1 (PubMed:29198525). Plays an auxiliary role in post-translational transport of small presecretory proteins across endoplasmic reticulum (ER). May function as an allosteric modulator for SEC61 channel-forming translocon complex, likely cooperating with SEC62 to enable the productive insertion of these precursors into SEC61 channel. Appears to specifically regulate translocation of precursors having inhibitory residues in their mature region that weaken channel gating. May also play a role in apoptosis and cell proliferation (By similarity). Monomer and homooligomer; homooligomerization via the interdomain linker inactivates the chaperone activity and acts as a storage of HSPA5/BiP molecules (PubMed:26473973). Interacts with DNAJC1 (via J domain) (By similarity). Component of an EIF2 complex at least composed of CELF1/CUGBP1, CALR, CALR3, EIF2S1, EIF2S2, HSP90B1 and HSPA5 (By similarity). Part of a large chaperone multiprotein complex comprising DNAJB11, HSP90B1, HSPA5, HYOU, PDIA2, PDIA4, PDIA6, PPIB, SDF2L1, UGGT1 and very small amounts of ERP29, but not, or at very low levels, CALR nor CANX (By similarity). Interacts with TMEM132A and TRIM21. May form a complex with ERLEC1, OS9, SEL1L and SYVN1. Interacts with DNAJC10 (By similarity). Interacts with DNAJB9/ERdj4; leading to recruit HSPA5/BiP to ERN1/IRE1 (PubMed:29198525). Interacts with ERN1/IRE1; interaction takes place following interaction with DNAJB9/ERdj4 and leads to inactivate ERN1/IRE1 (PubMed:29198525). Interacts with MX1 (By similarity). Interacts with METTL23. Interacts with CEMIP; the interaction induces calcium leakage from the endoplasmic reticulum and cell migration. Interacts with PCSK4 form; the interaction takes place in the endoplasmic reticulum. Interacts with CIPC. Interacts with CCDC88B (via C-terminus); the interaction opposes ERN1-mediated JNK activation, protecting against apoptosis. Interacts with INPP5K; necessary for INPP5K localization at the endoplasmic reticulum. Interacts with LOXL2; leading to activate the ERN1/IRE1-XBP1 pathway of the unfolded protein response (By similarity). Interacts with CLU under stressed condition; interaction increases CLU protein stability; facilitates its retrotranslocation and redistribution to the mitochondria; cooperatively suppress stress-induced apoptosis by stabilizing mitochondrial membrane integrity (By similarity). Interacts with CCDC47 (By similarity). Interacts with CLN3 (By similarity). Interacts with KIAA1324; may regulate the function of HSPA5 in apoptosis and cell proliferation. Interacts with CASP7 (By similarity).

EXTERNAL LINKS

HSPA5

Endoplasmic reticulum chaperone BiP

HSPA5

Molecular Synopsis