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Ste20‐like kinase (SLK), a regulatory kinase for polo‐like kinase (Plk) during the G2/M transition in somatic cells
Author(s) -
EllingerZiegelbauer Heidrun,
Karasuyama Hajime,
Yamada Eitaro,
Tsujikawa Kazutake,
Todokoro Kazuo,
Nishida Eisuke
Publication year - 2000
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.2000.00337.x
Subject(s) - biology , cyclin dependent kinase 1 , polo like kinase , microbiology and biotechnology , cyclin dependent kinase 2 , plk1 , ask1 , map kinase kinase kinase , cyclin dependent kinase 4 , cyclin dependent kinase 9 , kinase , mitogen activated protein kinase kinase , cell cycle , map2k7 , cdc25 , protein kinase a , biochemistry , cell
Background Activation of the cyclin‐dependent kinase cdc2‐cyclin B1 at the G2/M transition of the cell cycle requires dephosphorylation of threonine‐14 and tyrosine‐15 in cdc2, which in higher eukaryotes is brought about by the Cdc25C phosphatase. In Xenopus , there is evidence that a kinase cascade comprised of xPlkk1 and Plx1, the Xenopus polo‐like kinase 1, plays a key role in the activation of Cdc25C during oocyte maturation. In the mammalian somatic cell cycle, a polo‐like kinase homologue (Plk1) also functions during mitosis, but a kinase upstream of Plk is still unknown. Results We show here that human Ste20‐like kinase (SLK), which is a ubiquitously expressed mammalian protein related to xPlkk1, can phosphorylate and activate murine Plk1. During progression through the G2 phase of the mammalian cell cycle, the activity of endogenous SLK is increased. The amount of SLK protein is decreased in quiescent and differentiating cells. Treatment with okadaic acid induces a phosphorylation‐dependent enhancement of SLK activity. Conclusions We propose that SLK has a role in the regulation of Plk1 activity in actively dividing cells during the somatic cell cycle. SLK itself is suggested to be regulated by phosphorylation.