Participates in the regulation of systemic glucose homeostasis, where it negatively regulates insulin granule biogenesis in pancreatic islet beta cells (PubMed:24711543). Also regulates glucagon granule production in pancreatic alpha cells (PubMed:25737957). Inhibits nuclear translocation of the transcriptional coregulator PHB2 and may enhance estrogen receptor alpha (ESR1) transcriptional activity in breast cancer cells (By similarity). Interacts with PHB2 (By similarity). Expressed in pancreatic islet (insulin granules of islet alpha and beta cells) and brain (at protein level). Viable and fertile with normal body weight gain. Mice exhibit postprandial hyperinsulinemia and hyperglycemia, and impaired glucose tolerance. Three month old animals show severe insulin resistance in liver and muscle tissue, probably due to chronic insulin exposure.