In neurons, plays a role in the regulation of intracellular Ca(2+), possibly by acting as an activator of ATP2A2/SERCA2, thus increasing the efficiency with which Ca(2+) is removed from the cytoplasm (By similarity). Inhibits differentiation of embryonic stem cells into neurons and inhibits neurite outgrowth, likely as a result of its role in intracellular Ca(2+) regulation (By similarity). In pancreatic beta cells, lowers Ca(2+) levels in the endoplasmic reticulum and enhances glucose-stimulated insulin secretion (PubMed:34513312). Interacts with ATPase ATP2A2/SERCA2 (By similarity). Interacts with ATPase ATP2A3/SERCA3; the interaction occurs at low levels in low glucose conditions and is increased by high glucose levels (PubMed:34513312). Highly expressed in pancreatic islets where it is enriched in the insulin-producing beta cells.