Discovery of a novel target for the dysglycemic chromogranin A fragment pancreastatin: interaction with the chaperone GRP78 to influence metabolism.

ABSTRACT:

Rationale

The chromogranin A-derived peptide pancreastatin (PST) is a dysglycemic, counter-regulatory peptide for insulin action, especially in liver. Although previous evidence for a PST binding protein has been reported, such a receptor has not been identified or sequenced.

Methods and results

We used ligand affinity to purify the PST target, with biotinylated human PST (hCHGA273-301-amide) as "bait" and mouse liver homogenate as "prey", and identified GRP78 (a.k.a. "78 kDa Glucose Regulated Protein", HSPA5, BIP) as a major interacting partner of PST. GRP78 belongs to the family of heat shock proteins (chaperones), involved in several cellular processes including protein folding and glucose metabolism. We analyzed expression of GRP78 in the absence of PST in a mouse knocko

SUBMITTER: Biswas N 

PROVIDER: S-EPMC3896336 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature