Interaction between cyclin T1 and SCFSKP2 targets CDK9 for ubiquitination and degradation by the proteasome

R. E. Kiernan, S. Emiliani, K. Nakayama, A. Castro, J. C. Labbé, T. Lorca, K. I. Nakayama, M. Benkirane

Research output: Contribution to journalArticlepeer-review

76 Citations (Scopus)


CDK9 paired with cyclin T1 forms the human P-TEFb complex and stimulates productive transcription through phosphorylation of the RNA polymerase II C-terminal domain. Here we report that CDK9 is ubiquitinated and degraded by the proteasome whereas cyclin T1 is stable. SCFSKP2 was recruited to CDK9/cyclin T1 via cyclin T1 in an interaction requiring its PEST domain. CDK9 ubiquitination was modulated by cyclin T1 and p45SKP2. CDK9 accumulated in p45SKP2-/- cells, and its expression during the cell cycle was periodic. The transcriptional activity of CDK9/cyclin T1 on the class II major histocompatibility complex promoter could be regulated by CDK9 degradation in vivo. We propose a novel mechanism whereby recruitment of SCFSKP2 is mediated by cyclin T1 while ubiquitination occurs exclusively on CDK9.

Original languageEnglish
Pages (from-to)7956-7970
Number of pages15
JournalMolecular and cellular biology
Issue number23
Publication statusPublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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