Open AccessProtein-tyrosine phosphatase activity of CD45 is activated by sequential phosphorylation by two kinases.
Author(s) -
David R. Stover,
Kenneth A. Walsh
Publication year - 1994
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.14.8.5523
Subject(s) - protein tyrosine phosphatase , phosphorylation , biology , protein phosphorylation , tyrosine phosphorylation , casein kinase 1 , receptor tyrosine kinase , biochemistry , autophagy related protein 13 , tyrosine kinase , kinase , tyrosine , microbiology and biotechnology , phosphatase , sh2 domain , serine , phosphorylation cascade , protein kinase a , signal transduction
We describe a potential regulatory mechanism for the transmembrane protein-tyrosine phosphatase CD45. Phosphorylation on both tyrosine and serine residues in vitro results in an activation of CD45 specifically toward one artificial substrate but not another. The activation of these kinases appears to be order dependent, as it is enhanced when phosphorylation of tyrosine precedes that of serine but phosphorylation in the reverse order yields no activation. Any of four protein-tyrosine kinases tested, in combination with the protein-serine/threonine kinase, casein kinase II, was capable of mediating this activation in vitro. The time course of phosphorylation of CD45 in response to T-cell activation is consistent with the possibility that this regulatory mechanism is utilized in vivo.