Kir, a novel Ras-family G-protein, induces invasive pseudohyphal growth in Saccharomyces cerevisiae.
Kir belongs to a novel class of Ras-family G-proteins which includes Gem and Rad. These proteins are unique among Ras super-family G-proteins since their expression is under transcriptional regulation in mammalian cells. To gain insight into the function of Kir, we took advantage of the well-defined signal transduction pathways of yeast. When kir is expressed in Saccharomyces cerevisiae, the transformants form pseudohyphae and exhibit invasive properties characteristics of yeast cells undergoing a developmental transition induced by nitrogen starvation. Analysis of pseudohyphal signaling pathway mutants suggests that the Kir-induced pseudohyphae formation requires a MAP kinase cascade involving ste20, ste11, ste7 but not ste5 gene products. Furthermore, our results are consistent with the idea that Kir functions upstream of the STE20 kinase which plays a critical role in two distinct MAP kinase cascades.
Dorin
D
D
Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095-1489, USA.
Cohen
L
L
Del Villar
K
K
Poullet
P
P
Mohr
R
R
Whiteway
M
M
Witte
O
O
Tamanoi
F
F
D003001:Cloning, Molecular; D019204:GTP-Binding Proteins / Q000502:physiology*; D017874:Immediate-Early Proteins / Q000502:physiology*; D020559:Monomeric GTP-Binding Proteins; D009584:Nitrogen; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D014170:Transformation, Genetic
D017874:Immediate-Early Proteins; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins; D009584:Nitrogen