Example：10.1021/acsami.1c06204 or Chem. Rev., 2007, 107, 2411-2502
G1 cyclin–Cdk promotes cell cycle entry through localized phosphorylation of RNA polymerase II Science (IF47.728), Pub Date : 2021-10-15, DOI: 10.1126/science.aba5186 Mardo Kõivomägi, Matthew P. Swaffer, Jonathan J. Turner, Georgi Marinov, Jan M. Skotheim
Cell division is thought to be initiated by cyclin-dependent kinases (Cdks) inactivating key transcriptional inhibitors. In budding yeast, the G1 cyclin Cln3-Cdk1 complex is thought to directly phosphorylate the Whi5 protein, thereby releasing the transcription factor SBF and committing cells to division. We report that Whi5 is a poor substrate of Cln3-Cdk1, which instead phosphorylates the RNA polymerase II subunit Rpb1’s C-terminal domain on S5 of its heptapeptide repeats. Cln3-Cdk1 binds SBF-regulated promoters and Cln3’s function can be performed by the canonical S5 kinase Ccl1-Kin28 when synthetically recruited to SBF. Thus, we propose that Cln3-Cdk1 triggers cell division by phosphorylating Rpb1 at SBF-regulated promoters to promote transcription. Our findings blur the distinction between cell cycle and transcriptional Cdks to highlight the ancient relationship between these two processes.