Islet cell autoantigen 1 (ICA1 (commonly referred to as ICA69))

Islet cell autoantigen 1 is a BAR-domain cytosolic lipid-binding protein predominantly expressed in pancreatic islets and other neuroendocrine tissues. It regulates the trafficking and maturation of insulin secretory granules by forming complexes with PICK1 and associating with Rab2, ensuring proper proinsulin processing and insulin secretion in β cells. As an autoantigen, ICA1 is implicated in the pathogenesis of type 1 diabetes mellitus, where loss of central tolerance leads to autoreactive T cell and autoantibody attack against β cells. ICA1 is also a marker in primary Sjögren's syndrome and may play roles in neuronal signaling, pain modulation, and fertility processes. Detection of ICA1 autoantibodies is used as a biomarker for risk of progression to type 1 diabetes.

Other names

ICA69islet cell autoantigen 69 kDaICA1 proteinislet cell antibody 69 kDa

In autoimmunity, the mechanism involves loss of immune tolerance to ICA1, resulting in autoantibody and autoreactive T cell responses. Drug actions, where relevant, would theoretically involve modulating immune recognition or affecting downstream consequences of vesicle trafficking, but no specific drugs are referenced in available sources.