This gene encodes a type I transmembrane protein and member of the immunoglobulin superfamily of cell adhesion molecules. The encoded protein localizes to adherens junctions in pancreatic beta cells and regulates insulin secretion. Autoantibodies against the encoded protein have been detected in serum from patients with type 1 diabetes. This gene may also play a role in glomerular development and decreased expression of this gene has been observed in human glomerular diseases. This gene and the related opposite-strand gene nephrin (GeneID: 527362) are regulated by a bidirectional promoter.