The plant-specific kinase CDKF;1 is involved in activating phosphorylation of cyclin-dependent kinase-activating kinases in Arabidopsis.

Cyclin-dependent kinases (CDKs) play essential roles in coordinate control of cell cycle progression. Activation of CDKs requires interaction with specific cyclin partners and phosphorylation of their T-loops by CDK-activating kinases (CAKs). The Arabidopsis thaliana genome encodes four potential CAKs. CAK2At (CDKD;3) and CAK4At (CDKD;2) are closely related to the vertebrate ...
CAK, CDK7/p40MO15; they interact with cyclin H and phosphorylate CDKs, as well as the C-terminal domain (CTD) of the largest subunit of RNA polymerase II. CAK1At (CDKF;1) shows cyclin H-independent CDK-kinase activity and can activate a heterologous CAK, Mcs6, in fission yeast. In Arabidopsis, CAK1At is a subunit of a protein complex of 130 kD, which phosphorylates the T-loop of CAK2At and CAK4At and activates the CTD-kinase activity of CAK4At in vitro and in root protoplasts. These results suggest that CAK1At is a novel CAK-activating kinase that modulates the activity of CAK2At and CAK4At, thereby controlling CDK activities and basal transcription in Arabidopsis.
Mesh Terms:
Animals, Arabidopsis, Arabidopsis Proteins, Cells, Cultured, Cyclin H, Cyclin-Dependent Kinases, Cyclins, Enzyme Activation, Insects, Macromolecular Substances, Molecular Sequence Data, Phosphorylation, Protein Kinases, Protein Structure, Tertiary, Protein-Serine-Threonine Kinases, Protoplasts, Saccharomyces cerevisiae, Schizosaccharomyces
Plant Cell
Date: Nov. 01, 2004
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