CDNA CLONING OF A NOVEL PROTEIN-TYROSINE-PHOSPHATASE WITH HOMOLOGY TOCYTOSKELETAL PROTEIN-4.1 AND ITS EXPRESSION IN T-LINEAGE CELLS

Reversible tyrosine phosphorylation plays important regulatory roles i n various cellular events including the differentiation and function o f lymphocytes. Here we report the cDNA cloning of a non-receptor type protein tyrosine phosphatase, PTP36, which is expressed in murine thym us. PTP36 was a new member of a tyrosine phosphatase subfamily defined by MEG-01 and PTPH1, which had a C-terminal phosphatase domain as wel l as an N-terminal domain with homology to cytoskeletal-associated pro teins like band 4.1, ezrin, and talin. In addition, we found a putativ e SH3-binding motif in PTP36 but not in MEC-01 or PTPH1. PTP36 was exp ressed in cells of both hematopoietic and non-hematopoietic origins. I n thymocytes subpopulations, PTP36 was preferentially expressed in dou ble positive stage cells. The change of PTP36 expression level along w ith T cell maturation suggests its involvement in the regulation of T cell development. (C) 1994 Academic Press, Inc.