GRP78 Antibody / BiP / HSPA5

HSPA5 (heat shock 70kDa protein 5), also known as glucose-regulated protein, 78kD (GRP78), BiP (Binding-immunoglobulin protein), is a member of the heat-shock protein-70 (HSP70) family and is involved in the folding and assembly of proteins in the endoplasmic reticulum. GRP78/BiP is also an essential component of the translocation machinery, as well as playing a role in retrograde transport across the ER membrane of aberrant proteins destined for degradation by the proteasome. Shen et al. (2002) concluded that GRP78 retains ATF6 in the ER by inhibiting its Golgi localization signals and that dissociation of GRP78 during ER stress allows ATF6 to be transported to the Golgi. The findings of Shen et al. (2002) demonstrated that GRP78 is a key element in sensing the folding capacity within the ER.