BANK1 Background Information BANK1 (B-cell scaffold protein with ankyrin repeats) is a 785 amino acid protein that contains one DBB domain and two ANK (ankyrin) repeats. Expressed in a variety of B-cells with particularly high expression in CD19(+) B-cells, BANK1 interacts with Lyn, IP3R-I and IP3R-II and is involved in B-cell receptor-induced calcium mobilization from intracellular calcium stores. Via its association with Lyn, BANK1 promotes Lyn-mediated tyrosine phosphorylation of IP3R-I and IP3R-II, an event that activates B-cells and may be required for antigen-induced immune responses within the body. Defects in the gene encoding BANK1 increase the genetic susceptibility to systemic lupus erythematosus (SLE), a chronic inflammatory disorder that affects joints, skin, serosal membranes and kidney tissue. BANK1 exists as four isoforms that are produced by alternative splicing events.
