Title: | Ca2+ signal is generated only once in the mating pheromone response pathway in Saccharomyces cerevisiae |
Author(s): | Nakajima-Shimada J; Sakaguchi S; Tsuji FI; Anraku Y; Iida H; |
Address: | "Department of Parasitology, Juntendo University School of Medicine, Tokyo, Japan" |
ISSN/ISBN: | 0386-7196 (Print) 0386-7196 (Linking) |
Abstract: | "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" |
Keywords: | "Calcium/*metabolism *Calcium Signaling/drug effects Cell Cycle/drug effects Cell Differentiation Heterotrimeric GTP-Binding Proteins/metabolism Mating Factor Peptides/*metabolism/pharmacology Plasmids/genetics Receptors, Cell Surface/*metabolism Saccharom;" |
Notes: | "MedlineNakajima-Shimada, J Sakaguchi, S Tsuji, F I Anraku, Y Iida, H eng Research Support, Non-U.S. Gov't Japan 2000/07/08 Cell Struct Funct. 2000 Apr; 25(2):125-31. doi: 10.1247/csf.25.125" |