Protein Tyrosine Phosphatase, Non Receptor Type 23 (PTPN23)

PTPN23, from a gastric cancer cell line. The predicted protein contains at least 1,636 amino acids and has several features distinct from those in previously identified PTPs, the most striking of which is the sequence VHCSSG instead of the invariant VHCSAG sequence at the PTP active center. PTPN23 contains a zinc-hand domain, which the authors called a 'His domain' (HD); several SH3-binding motifs; a tyrosine phosphatase domain; a C-terminal PEST motif; and an N-terminal domain similar to yeast BRO1, mouse rhophilin, and human AIP1. It appears to be the homolog of rat PTP-TD14 which has been found to inhibit activated H-ras-mediated cell transformation. Northern blot analysis in rat revealed ubiquitous expression of a 6-kb PTPN23 transcript.