Interactions of Cdk7 and Kin28 with Hint/PKCI-1 and Hnt1 histidine triad proteins.

Cyclin-dependent kinase 7 (Cdk7) forms a trimeric complex with cyclin H and Mat1 to form the mammalian Cdk-activating kinase, CAK, as well as a part of the basal transcription factor TFIIH, where Cdk7 phosphorylates the C-terminal domain (CTD) of the large subunit of RNA polymerase II. Here, we report a ...
novel interaction between Cdk7 and a histidine triad (HIT) family protein, Hint/PKCI-1. This interaction was initially observed in a yeast two-hybrid study and subsequently verified by co-immunoprecipitation and subcellular localization studies, where overexpression of Cdk7 leads to partial relocalization of Hint to the nucleus. The physical association is independent of cyclin H binding or Cdk7 kinase activity and is conserved between the related Sacharomyces cerevisiae CTD kinase Kin28 and the HIT protein Hnt1. Furthermore, combination of a disruption of HNT1 and a KIN28 temperature-sensitive allele in S. cerevisiae led to highly elongated cell morphology and reduced colony formation, indicating a genetic interaction between KIN28 and HNT1. The physical and genetic interactions of Hint and Hnt1 with Cdk7 and Kin28 suggest a role for this class of histidine triad proteins in the regulation of Cdk7 and Kin28 functions.
Mesh Terms:
Alleles, Animals, Blotting, Western, Cell Nucleus, Cyclin H, Cyclin-Dependent Kinases, Cyclins, Fluorescent Antibody Technique, Glutathione Transferase, Histidine, Humans, Mutagenesis, Phosphorylation, Plasmids, Precipitin Tests, Protein Binding, Protein Structure, Tertiary, Protein-Serine-Threonine Kinases, Protein-Tyrosine Kinases, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Temperature, Tumor Cells, Cultured, Two-Hybrid System Techniques
J. Biol. Chem.
Date: Nov. 10, 2000
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