title: A cyclin-dependent kinase-activating kinase (CAK) in budding yeast unrelated to vertebrate CAK.
abstract: Progress through the cell cycle is governed by the cyclin-dependent kinases (CDKs), the activation of which requires phosphorylation by the CDK-activating kinase (CAK). In vertebrates, CAK is a trimeric enzyme containing CDK7, cyclin H, and MAT1. CAK from the budding yeast Saccharomyces cerevisiae was identified as an unusual 44-kilodalton protein kinase, Cak1, that is only distantly related to CDKs. Cak1 accounted for most CAK activity in yeast cell lysates, and its activity was constant throughout the cell cycle. The CAK1 gene was essential for cell viability. Thus, the major CAK in S. cerevisiae is distinct from the vertebrate enzyme, suggesting that budding yeast and vertebrates may have evolved different mechanisms of CDK activation.
authors.affiliation: Department of Physiology, University of California, San Francisco, 94143-0444, USA.
authors.forename: F H
authors.initials: FH
authors.lastname: Espinoza
authors.forename: A
authors.initials: A
authors.lastname: Farrell
authors.forename: H
authors.initials: H
authors.lastname: Erdjument-Bromage
authors.forename: P
authors.initials: P
authors.lastname: Tempst
authors.forename: D O
authors.initials: DO
authors.lastname: Morgan
mesh_terms: D000595:Amino Acid Sequence; D042846:CDC2-CDC28 Kinases; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002453:Cell Cycle; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D004789:Enzyme Activation; D017353:Gene Deletion; D005800:Genes, Fungal; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D000095043:Cyclin-Dependent Kinase-Activating Kinase
chemical_list: D011993:Recombinant Fusion Proteins; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; D017489:CDC28 Protein Kinase, S cerevisiae; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D000095043:Cyclin-Dependent Kinase-Activating Kinase