GRP94 is essential for mesoderm induction and muscle development because it regulates insulin-like growth factor secretion.

Because only few of its client proteins are known, the physiological roles of the endoplasmic reticulum chaperone glucose-regulated protein 94 (GRP94) are poorly understood. Using targeted disruption of the murine GRP94 gene, we show that it has essential functions in embryonic development. grp94-/- embryos die on day 7 of gestation, fail to develop mesoderm, primitive streak, or proamniotic cavity.

Radicicol-sensitive peptide binding to the N-terminal portion of GRP94.

GRP94 is a molecular chaperone that carries immunologically relevant peptides from cell to cell, transferring them to major histocompatibility proteins for presentation to T cells. Here we examine the binding of several peptides to recombinant GRP94 and study the regulation and site of peptide binding. We show that GRP94 contains a peptide-binding site in its N-terminal 355 amino acids.