Reconstitution of regulated phosphorylation of FcepsilonRI by a lipid raft-excluded protein-tyrosine phosphatase |
| |
Authors: | Young Ryan M Zheng Xinmin Holowka David Baird Barbara |
| |
Institution: | Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA. |
| |
Abstract: | To examine the exquisite regulation of IgE-FcepsilonRI tyrosine phosphorylation by Lyn kinase that is stimulated by antigen-mediated cross-linking, we utilized co-expression of FcepsilonRI and Lyn in Chinese hamster ovary cells, which results in high basal levels of Lyn kinase activity and spontaneous phosphorylation of FcepsilonRI. We found that co-expression of a lipid raft-excluded transmembrane tyrosine phosphatase, PTPalpha, suppresses Lyn kinase activity and markedly reduces the level of spontaneous phosphorylation of FcepsilonRI, while facilitating its antigen-stimulated phosphorylation. Other tyrosine phosphatases, including SHP-1, CD45, and a lipid raft-preferring chimeric version of PTPalpha fail to reconstitute antigen-dependent FcepsilonRI phosphorylation. We concluded that both substrate specificity and submembrane location are critical to phosphatase-mediated regulation of Lyn kinase activity that supports activation of FcepsilonRI. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|