Molecular and General Genetics MGG

, Volume 256, Issue 4, pp 365–375

Mutational analysis of Cak1p, an essential protein kinase that regulates cell cycle progression

  • K. T. Chun
  • M. G. Goebl

DOI: 10.1007/s004380050580

Cite this article as:
Chun, K. & Goebl, M. Mol Gen Genet (1997) 256: 365. doi:10.1007/s004380050580


In Saccharomyces cerevisiae, entry into S phase requires the activation of the protein kinase Cdc28p through binding with cyclin Clb5p or Clb6p, as well as the destruction of the cyclin-dependent kinase inhibitor Sic1p. Mutants that are defective in this activation event arrest after START, with unreplicated DNA and multiple, elongated buds. These mutants include cells defective in CDC4, CDC34 or CDC53, as well as cells that have lost all CLB function. Here we describe mutations in another gene, CAK1, that lead to a similar arrest. Cells that are defective in CAK1 are inviable and arrest with a single nucleus and multiple, elongated buds. CAK1 encodes a protein kinase most closely related to the Cdc2p family of protein kinases. Mutations that lead to the production of an inactive kinase that can neither autophosphorylate, nor phosphorylate Cdc28p in vitro are also incapable of rescuing a cell with a deletion of CAK1. These results underscore the importance of the Cak1p protein kinase activity in cell cycle progression.

Key words CAK Cell cycle Cyclin-dependent kinase Elongated buds Protein kinase 

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • K. T. Chun
    • 1
  • M. G. Goebl
    • 1
  1. 1.The Walther Oncology Center, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202-5122, USAIN
  2. 2.Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202-5122, USA Tel. +1 317-274-2055; fax +1-317-274-4686IN

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