Glucose regulated protein, GRP78 of 654 aas.  GRP78, a member of the ER stress protein family.  It can relocate to the surface of cancer cells, playing a role in promoting cell proliferation and metastasis. GRP78 consists of two major functional domains: the ATPase and protein/peptide-binding domains. The protein/peptide-binding domain of cell-surface GRP78 has served as a novel functional receptor for delivering cytotoxic agents (e.g., a apoptosis-inducing peptide or taxol) across the cell membrane. The ATPase domain of GRP78 (GRP78ATPase) has potential as a transmembrane delivery system of cytotoxic agents including nucleotides (e.g., ATP-based nucleotide triphosphate analogs) (Hughes et al. 2016). May also play a role in facilitating the assembly of multimeric protein complexes inside the endoplasmic reticulum (Evensen et al. 2013). It is involved in the correct folding of proteins and degradation of misfolded proteins via its interaction with DNAJC10, probably to facilitate the release of DNAJC10 from its substrate (Evensen et al. 2013).