Involvement of actin and polarisome in morphological change during spore germination of Saccharomyces cerevisiae

Yeast. 2005 Jan 30;22(2):129-39. doi: 10.1002/yea.1205.


We studied the morphological changes of Saccharomyces cerevisiae ascospores during germination. Initiation of germination is followed by polarization of actin patches, maintaining their localization to the site of cell surface growth. Loss of polarisome components, Spa2p, Pea2p, Bud6p or Bni1p, results in depolarization of actin patches. Green fluorescent protein-fused polarisome components exhibit the polarized localization, implying that polarisome is involved in the polarized outgrowth during germination. At the late stage of germination, we found that actin patches temporally depolarize before bud emergence. The observation that loss of Cla4p extends the polarized growth period suggests that Cla4p is involved in the actin-depolization step. Actin polarization in the initial stage is accelerated by overexpression of Ras2p, whereas hyperpolarization is continuously observed by overexpression of Rho1p. Thus, yeast spore germination is a morphological event that is regulated by a number of factors implicated in mitotic bud morphogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / physiology*
  • Blotting, Western
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Cell Polarity / physiology
  • Cell Wall / physiology
  • Cell Wall / ultrastructure
  • Microscopy, Electron
  • Microscopy, Fluorescence
  • Morphogenesis / physiology
  • Mutation
  • Protein-Serine-Threonine Kinases / physiology
  • Saccharomyces cerevisiae / growth & development*
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / physiology
  • Spores, Fungal / growth & development
  • Spores, Fungal / ultrastructure
  • Thiazoles / pharmacology
  • Thiazolidines
  • rho GTP-Binding Proteins / physiology


  • Actins
  • Bridged Bicyclo Compounds, Heterocyclic
  • Saccharomyces cerevisiae Proteins
  • Thiazoles
  • Thiazolidines
  • CLA4 protein, S cerevisiae
  • Protein-Serine-Threonine Kinases
  • RHO1 protein, S cerevisiae
  • rho GTP-Binding Proteins
  • latrunculin A