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Two mechanisms activate PTPα during mitosis
Author(s) -
Zheng XinMin,
Shalloway David
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.21.6037
Subject(s) - mitosis , biology , protein tyrosine phosphatase , proto oncogene tyrosine protein kinase src , microbiology and biotechnology , phosphatase , mitotic exit , phosphorylation , biochemistry , cell division , spindle apparatus , cell
We show that, dependent on serine hyperphosphorylation, protein tyrosine phosphatase α (PTPα) is activated by two different mechanisms during mitosis: its specific activity increases and its inhibitory binding to Grb2 decreases. The latter effect probably abates Grb2 inhibition of the phosphotyrosine displacement process that is required specifically for Src dephosphorylation and causes a mitotic increase in transient PTPα‐Src binding. Thus, part of the increased protein tyrosine phosphatase activity may be specific for Src family members. These effects cease along with Src activation when cells exit mitosis. Src is not activated in mitosis in PTPα‐knockout cells, indicating a unique mitotic role for this phosphatase. The activation of PTPα, combined with the effects of mitotic Cdc2‐mediated phosphorylations of Src, quantitatively accounts for the mitotic activation of Src, indicating that PTPα is the membrane‐bound, serine phosphorylation‐activated, protein tyrosine phosphatase that activates Src during mitosis.