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.

• PMID: 8570176
• PubMed

Reference Type

Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, P.H.S.

Authors

Dorin D, Cohen L, Del Villar K, Poullet P, Mohr R, Whiteway M, Witte O, Tamanoi F

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