Protein Tyrosine Phosphatase (PC12, Br7,S1) Family: Expression Characterization in the Adult Human and Mouse

Protein tyrosine phosphatases (PTPs) play important roles in modulating signals transduced by tyrosine kinases. Certain phosphatases have been implicated as having important roles in embryonic development as well as in adult physiology. Although both kinases and phosphatases are equally important in regulating signal transduction, phosphatases as a group have not been well characterized. Thus, characterization of sequence, expression, and biological function for additional phosphatases is informative. PTPBr7/PC12 and PTPSl are mouse receptor PTPs sharing similar amino acid sequences. Northern blot analysis demonstrated expression of these genes in adult rodent brain and revealed previously uncharacterized transcripts in the brain and other tissues. Our results demonstrate that PTPBr7/PC12 and PTPSl are members of a larger family of PTPs. We have identified two novel family members as well as several novel transcriptional splice variants from both human and mouse colon cDNA libraries. Expression analysis demonstrated that the various mRNA transcripts are differentially expressed, with the highest levels found in the brain, intestinal tract, uterus, and placenta. In situ hybridization analysis of mouse brain and intestinal tissues established that each isoform has a unique expression pattern in specific cell populations as well as in tissue regions. Furthermore, these restricted patterns suggest that the encoded family of phosphatases may play roles in modulating signal transduction pathways important for specific cell types and biological processes.