Analysis of CAK activities from human cells

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

The cdk-activating kinase (CAK) activates cyclin-dependent kinases (cdks) that control cell-cycle progression by phosphorylating a threonine residue conserved in cdks. CAK from humans contains p40(MO15) (cdk7), cyclin H and MAT1, which are also subunits of transcription factor IIH where they phosphorylate the C-terminal domain of the large subunit of RNA polymerase II. In contrast, budding yeast Cak1p is a monomeric enzyme without C-terminal domain kinase activity. Here, we analyze CAK activities in HeLa cells using cdk2-affinity chromatography. In addition to MO15, a second CAK activity was detected that runs on gel filtration at 30-40 kDa. This activity phosphorylated and activated cdk2 and cdk6. Furthermore, this 'small CAK' activity resembled Cak1p rather than MO15 in terms of substrate specificity, reactivity to antibodies against MO15 and Cak1p, and sensitivity to 5'- fluorosulfonylbenzoyladenosine, an irreversible inhibitory ATP analog. Our findings suggest the presence of at least two different CAK activities in human cells.

Detaljer

Författare
Externa organisationer
  • Yale University
Forskningsområden

Nyckelord

Originalspråkengelska
Sidor (från-till)4213-4221
TidskriftEuropean Journal of Biochemistry
Volym267
Utgåva nummer13
StatusPublished - 2000 jul 17
PublikationskategoriForskning
Peer review utfördJa
Externt publiceradJa