| First Author | Wasmeier C | Year | 1996 |
| Journal | J Biol Chem | Volume | 271 |
| Issue | 30 | Pages | 18161-70 |
| PubMed ID | 8663434 | Mgi Jnum | J:34340 |
| Mgi Id | MGI:81800 | Doi | 10.1074/jbc.271.30.18161 |
| Citation | Wasmeier C, et al. (1996) Molecular cloning of phogrin, a protein-tyrosine phosphatase homologue localized to insulin secretory granule membranes. J Biol Chem 271(30):18161-70 |
| abstractText | An insulin granule membrane protein-tyrosine phosphatase (PTP) homologue, phogrin, was cloned by expression screening of a rat insulinoma cDNA library. The 3723-base pair cDNA encoded a transmembrane glycoprotein of 1004 amino acids (Mr 111876) that underwent post-translational proteolysis to 60-64-kDa products after a 30-min delay. The kinetics of proteolytic conversion (t1/2 = 45 min) and turnover (t1/2 = 12 h) were consistent with sorting and conversion in a late compartment of the secretory pathway. Studies on the native beta-cell protein suggested that the COOH-terminal PTP domain was on the cytosolic face of the secretory granule. The lumenal segment was comprised of a protease-resistant globular domain of around 25 kDa. Its localization and topology is thus consistent with a transmembrane receptor function related to granule biogenesis, exocytosis, or subsequent membrane recovery, and it should prove to be a useful cell biological marker for the granule membrane. High expression of the mRNA (5.4 kilobases) and protein was evident in islets, pancreatic alpha- and beta-cell tumor lines, brain cells, and other cells of neuroendocrine lineage. It is closely related to the diabetic autoantigen ICA512 (IA-2) (42% identity overall; 80% in the 260-amino acid PTP domain) and thus a potential target of autoimmunity in diabetes mellitus. |
