title: Comparison of Cak1p-like cyclin-dependent kinase-activating kinases.
abstract: Cyclin-dependent kinases (cdks) coordinate progression through the eukaryotic cell cycle and require phosphorylation by a cdk-activating kinase (CAK) for full activity. In most eukaryotes Cdk7 is the catalytic subunit of a heterotrimeric CAK (Cdk7-cyclin H-Mat1) that is also involved in transcription as part of the transcription factor IIH complex. The Saccharomyces cerevisiae CAK, Cak1p, is a monomeric protein kinase with an atypical sequence and unusual biochemical properties compared with trimeric CAKs and other protein kinases. We sought to determine whether these properties were shared by a small group of monomeric CAKs that can function in place of CAK1 in S. cerevisiae. We found that Schizosaccharomyces pombe Csk1, Candida albicans Cak1, and Arabidopsis thaliana Cak1At, like Cak1p, all displayed a preference for cyclin-free cdk substrates, were insensitive to the protein kinase inhibitor 5'-fluorosulfonylbenzoyladenosine (FSBA), and were insensitive to mutation of a highly conserved lysine residue found in the nucleotide binding pocket of all protein kinases. The S. pombe and C. albicans kinases also resembled Cak1p in their kinetics of nucleotide and protein substrate utilization. Conservation of these unusual properties in fungi and plants points to shared evolutionary requirements not met by Cdk7 and raises the possibility of developing antifungal agents targeting CAKs.
authors.affiliation: Departments of Cell Biology and Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520-8024, USA.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Tsakraklides
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Solomon
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D017360:Arabidopsis / Q000378:metabolism; D042846:CDC2-CDC28 Kinases; D002176:Candida albicans / Q000378:metabolism; D002460:Cell Line; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007313:Insecta; D007700:Kinetics; D008239:Lysine / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism; D029867:Xenopus Proteins; D014982:Xenopus laevis; D000095043:Cyclin-Dependent Kinase-Activating Kinase
chemical_list: D000935:Antifungal Agents; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins; D000255:Adenosine Triphosphate; D005982:Glutathione Transferase; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495891:Cdk2 protein, Xenopus; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D008239:Lysine; D000409:Alanine; D000095043:Cyclin-Dependent Kinase-Activating Kinase