PMID: 7518460Jul 29, 1994Paper

Phosphorylation and identification of a major tyrosine phosphorylation site in protein tyrosine phosphatase 1C.

The Journal of Biological Chemistry
P BouchardS H Shen

Abstract

Protein tyrosine phosphatase 1C (PTP1C) was the first member of the protein tyrosine phosphatase family demonstrated to contain the src homology 2 (SH2) domain. This enzyme is believed to play a role in regulating downstream signaling in hematopoietic cells since it was predominantly expressed in these cells. However, recent studies have revealed that the protein is expressed in other tissues as well. This report describes both the phosphorylation of PTP1C in non-hematopoietic cells treated with growth factors (in vivo) and incubation of purified PTP1C with a variety of protein kinases (in vitro). PTP1C was transiently phosphorylated in A431 and 293 cells and also when the purified enzyme was incubated with receptor protein tyrosine kinases. In vitro, the tyrosine-phosphorylated PTP1C underwent rapid auto-dephosphorylation, an effect which could be blocked by the addition of sodium vanadate. On the other hand, cells containing a PTP1C in which the catalytic site had been inactivated through mutagenesis, stably phosphorylated the phosphatase. These results suggested that PTP1C was responsible for its own auto-dephosphorylation. The sites of tyrosine phosphorylation were characterized from purified enzyme following treatment with...Continue Reading

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.