First Author | Lu J | Year | 1994 |
Journal | Biochem Biophys Res Commun | Volume | 204 |
Issue | 2 | Pages | 930-6 |
PubMed ID | 7980563 | Mgi Jnum | J:21080 |
Mgi Id | MGI:69129 | Doi | 10.1006/bbrc.1994.2549 |
Citation | Lu J, et al. (1994) Isolation, sequence and expression of a novel mouse brain cDNA, mIA-2, and its relatedness to members of the protein tyrosine phosphatase family. Biochem Biophys Res Commun 204(2):930-6 |
abstractText | This study describes the isolation of a putative transmembrane protein tyrosine phosphatase (PTP), mIA-2, from a mouse brain cDNA library. The cDNA encodes 979 amino acids containing a unique extracellular domain and a single intracellular catalytic domain. Expression of mIA-2 was found primarily in the central nervous system and in neuroendocrine cells. The sequence shares a high degree of homology with its human counterpart (92% identity), especially in the intracellular domain, which shows 99.3% identity between the two species. In both human and mouse IA-2, several substitutions were found in the highly conserved regions including an Ala to Asp substitution in the core sequence. Bacterial expression of a glutathione S-transferase fusion protein showed that mIA-2 had no enzyme activity with conventional substrates such as Raytide, myelin basic protein, angiotensin, RR-src and pNpp. When tested with the total tyrosine-phosphorylated cellular proteins isolated on an anti-phosphotyrosine antibody column, it also showed little, if any, enzyme activity. These findings suggest that mIA-2 is a new member of the transmembrane PTP family that either has very narrow substrate specificity perhaps requiring post-translational modification for enzyme activity or has a still unknown biological function. |