Relationship between the function and the location of G1 cyclins in S. cerevisiae

J Cell Sci. 2001 Dec;114(Pt 24):4599-611. doi: 10.1242/jcs.114.24.4599.

Abstract

The Saccharomyces cerevisiae cyclin-dependent kinase Cdc28 forms complexes with nine different cyclins to promote cell division. These nine cyclin-Cdc28 complexes have different roles, but share the same catalytic subunit; thus, it is not clear how substrate specificity is achieved. One possible mechanism is specific sub-cellular localization of specific complexes. We investigated the location of two G1 cyclins using fractionation and microscopy. In addition, we developed 'forced localization' cassettes, which direct proteins to particular locations, to test the importance of localization. Cln2 was found in both nucleus and cytoplasm. A substrate of Cln2, Sic1, was also in both compartments. Cytoplasmic Cln2 was concentrated at sites of polarized growth. Forced localization showed that some functions of Cln2 required a cytoplasmic location, while other functions required a nuclear location. In addition, one function apparently required shuttling between the two compartments. The G1 cyclin Cln3 required nuclear localization. An autonomous, nuclear localization sequence was found near the C-terminus of Cln3. Our data supports the hypothesis that Cln2 and Cln3 have distinct functions and locations, and the specificity of cyclin-dependent kinases is mediated in part by subcellular location.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • CDC28 Protein Kinase, S cerevisiae / genetics
  • CDC28 Protein Kinase, S cerevisiae / metabolism
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • Cell Nucleus / physiology
  • Cyclin G
  • Cyclins / genetics
  • Cyclins / metabolism
  • Cyclins / physiology*
  • Cytoplasm / genetics
  • Cytoplasm / metabolism
  • Cytoplasm / physiology
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Fungal Proteins / physiology*
  • G1 Phase* / genetics
  • Mutagenesis, Insertional
  • Nuclear Localization Signals / genetics
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Nuclear Proteins / physiology
  • Protein Transport / genetics
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology*

Substances

  • CLN2 protein, S cerevisiae
  • CLN3 protein, S cerevisiae
  • Cyclin G
  • Cyclins
  • Fungal Proteins
  • Nuclear Localization Signals
  • Nuclear Proteins
  • Saccharomyces cerevisiae Proteins
  • CDC28 Protein Kinase, S cerevisiae