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Negative regulation of mitosis by two functionally overlapping PTPases in fission yeast.
Author(s) -
Millar J.B.,
Russell P.,
Dixon J.E.,
Guan K.L.
Publication year - 1992
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 - 10.1002/j.1460-2075.1992.tb05601.x
Subject(s) - cdc25 , wee1 , biology , mitosis , microbiology and biotechnology , protein tyrosine phosphatase , cyclin dependent kinase 1 , phosphorylation , gene , genetics , cell cycle
We have identified a third protein tyrosine phosphatase (PTPase) gene in fission yeast, pyp2, encoding an 85 kDa protein. Disruption of pyp2 has no impact on cell viability, but pyp2 is essential in strains lacking the 60 kDa pyp1 PTPase. The two pyp PTPases are approximately 42% identical in their C‐terminal catalytic domains and share weak homology in their N‐terminal regions. Both genes play a role in inhibiting the onset of mitosis. Disruption of either gene rescues the G2 arrest caused by mutation of the cdc25 mitotic inducer, though the effect of pyp1‐disruption is more pronounced. Disruption of pyp1 advances mitosis, suppresses overexpression of the tyrosine kinase encoded by the wee1 mitotic inhibitor, and causes lethal mitotic catastrophe in cdc25 overproducer cells. Cells bearing inactive wee1 are unresponsive to disruption of pyp1. Overexpression of pyp1 or pyp2 delays the onset of mitosis by a wee1‐dependent mechanism. These data reveal an unexpected second role for protein tyrosine phosphorylation in the mitotic control that acts by promoting the inhibitory wee1 pathway.