PKC1, a protein kinase C homologue of Saccharomyces cerevisiae, participates in microtubule function through the yeast EB1 homologue, BIM1

Genes Cells. 2001 Sep;6(9):775-88. doi: 10.1046/j.1365-2443.2001.00461.x.

Abstract

Background: RSC is a chromatin-remodelling complex of Saccharomyces cerevisiae and essential for growth. Its catalytic subunit is encoded by the NPS1/STH1 gene. At the present time, little is known regarding the cellular function of RSC.

Results: To identify genes with functions related to NPS1, we screened high-copy suppressor genes for the temperature- and thiabendazole (TBZ)-sensitive mutant allele of NPS1, nps1-105. Amongst the suppressors we cloned PKC1/STT1 and BIM1 that encoded a homologue of mammalian protein kinase C and a conserved microtubule binding protein homologous to human EB1, respectively. Both the temperature sensitive mutation of PKC1, stt1, and the bim1 null mutation caused synthetic growth defects with nps1-105. A genetic analysis of the functional relationships between these genes revealed that PKC1 suppressed the defect of nps1-105 through the BIM1 function but not by the activation of the MPK1/MAPK pathway. The stt1 mutation alone showed TBZ sensitivity and delayed the G2-phase progression at semi-permissive temperatures. Both of these stt1 phenotypes were suppressed by the over-expression of BIM1. In addition, stt1 as well as nps1-105, mis-segregated a mini-chromosome at frequencies higher than the wild-type at a permissive temperature. The mis-segregation was enhanced in the nps1-105 stt1 double mutant.

Conclusion: These results suggest that Pkc1p plays a role which is relevant to microtubule functions and that this role is mediated by a hitherto unknown PKC signalling pathway and by Bim1p

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Northern
  • Blotting, Western
  • Cell Cycle Proteins / metabolism*
  • Cells, Cultured
  • Chromosome Segregation
  • DNA Primers / chemistry
  • Fluorescent Antibody Technique
  • Fungal Proteins / physiology*
  • Gene Dosage
  • Microtubule Proteins / metabolism*
  • Microtubules / metabolism*
  • Polymerase Chain Reaction
  • Protein Kinase C / physiology*
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae Proteins*
  • Signal Transduction
  • Thiabendazole / pharmacology

Substances

  • BIM1 protein, S cerevisiae
  • Cell Cycle Proteins
  • DNA Primers
  • Fungal Proteins
  • Microtubule Proteins
  • Saccharomyces cerevisiae Proteins
  • Pkc1 protein, Trichoderma reesei
  • Protein Kinase C
  • Thiabendazole