Ca2+ signal is generated only once in the mating pheromone response pathway in Saccharomyces cerevisiae

Cell Struct Funct. 2000 Apr;25(2):125-31. doi: 10.1247/csf.25.125.


The mating pheromone, alpha-factor, of the yeast Saccharomyces cerevisiae binds to the heterotrimeric G protein-coupled cell surface receptor of MATa cells and induces cellular responses necessary for mating. In higher eukaryotic cells, many hormones and growth factors rapidly mobilize a second messenger, Ca2+, by means of receptor-G protein signaling. Although striking similarities between the mechanisms of the receptor-G protein signaling in yeast and higher eukaryotes have long been known, it is still uncertain whether the pheromone rapidly mobilizes Ca2+ necessary for early events of the pheromone response. Here we reexamine this problem using sensitive methods for detecting Ca2+ fluxes and mobilization, and find no evidence that there is rapid Ca2+ influx leading to a rapid increase in the cytosolic free Ca2+ concentration. In addition, the yeast PLC1 deletion mutant lacking phosphoinositide-specific phospholipase C, a key enzyme for generating Ca2+ signals in higher eukaryotic cells, responds normally to the pheromone. These findings suggest that the receptor-G protein signaling does not utilize Ca2+ as a second messenger in the early stage of the pheromone response pathway. Since the receptor-G protein signaling does stimulate Ca2+ influx after early events have finished and this stimulation is essential for late events in the pheromone response pathway [Iida et al., (1990) J. Biol. Chem., 265: 13391-13399] Ca2+ may be used only once in the signal transduction pathway in unicellular eukaryotes such as yeast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / metabolism*
  • Calcium Signaling* / drug effects
  • Cell Cycle / drug effects
  • Cell Differentiation
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Mating Factor
  • Peptides / metabolism*
  • Peptides / pharmacology
  • Plasmids / genetics
  • Receptors, Cell Surface / metabolism*
  • Saccharomyces cerevisiae / physiology*
  • Second Messenger Systems
  • Signal Transduction
  • Type C Phospholipases / genetics


  • Peptides
  • Receptors, Cell Surface
  • Mating Factor
  • Type C Phospholipases
  • Heterotrimeric GTP-Binding Proteins
  • Calcium