Phogrin/IA-2beta and ICA512/IA-2 are two paralogs receptor-type protein-tyrosine phosphatases (RPTP), localized in secretory granules of various neuroendocrine cells. They have a signal peptide, an ectodomain, a single-pass transmembrane region, and a single intracellular PTP domain. Structural domains comprising this superfamily share the structure of the cited ectodomain.

Processing of pro IA-2 by furin-like hormone convertases produces mature IA-2, which lacks the signal peptide and an adjacent fragment. Upon exocytosis, the cytoplasmic domain of IA-2 is cleaved and moves to the nucleus where it enhances transcription of the insulin gene PMID:15596545. The mature ectodomain of IA-2 participates in adhesion to the extracellular matrix and is self-proteolysed in vitro by reactive oxygen species, which may be a new shedding mechanism PMID:18048354.