Civ1 (CAK in vivo), a novel Cdk-activating kinase.
Cyclin-dependent protein kinases (Cdks) play key roles in regulating cell division and gene expression. Most Cdks require binding of a cyclin and phosphorylation by a Cdk-activating kinase (CAK) to be active. We report the identification of Civ1 (CAK in vivo), a novel CAK activity in S. cerevisiae. Civ1 is most similar in sequence to the Cdks, but unlike them is active as a monomer and may thus be the founding member of a novel family of kinases. Civ1 binds tightly to and phosphorylates Cdc28, thereby allowing its subsequent activation by the binding of a cyclin. The CIV1 gene is essential for yeast cell viability, and Cdc28 phosphorylation and activity are conditionally inhibited in a civ1-4 temperature-sensitive mutant. Civ1 is the only CAK for which there are genetic data indicating that its activity is physiologically relevant in vivo.
Thuret
J Y
JY
Service de Biochimie et Génétique Molécularie, Gif-sur-Yvette, France.
Valay
J G
JG
Faye
G
G
Mann
C
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics*; D018844:Cyclin-Dependent Kinases; D017931:DNA Primers / Q000737:chemistry; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D000095043:Cyclin-Dependent Kinase-Activating Kinase
D018797:Cell Cycle Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D017346:Protein Serine-Threonine Kinases; D017489:CDC28 Protein Kinase, S cerevisiae; D018844:Cyclin-Dependent Kinases; D000095043:Cyclin-Dependent Kinase-Activating Kinase