The protein kinase homologue Ste20p is required to link the yeast pheromone response G-protein beta gamma subunits to downstream signalling components. |
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Authors: | E Leberer D Dignard D Harcus D Y Thomas and M Whiteway |
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Institution: | Biotechnology Research Institute, National Research Council of Canada. |
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Abstract: | In the yeast Saccharomyces cerevisiae the G-protein beta gamma subunits have been shown to trigger downstream events of the pheromone response pathway. We have identified a new gene, designated STE20, which encodes a protein kinase homologue with sequence similarity to protein kinase C, which is required to transmit the pheromone signal from G beta gamma to downstream components of the signalling pathway. Overproduction of the kinase suppresses the mating defect of dominant-negative G beta mutations providing genetic evidence for an interaction with G beta, and epistasis experiments show that this kinase functions after or at the same point as G beta gamma, but before any of the other currently identified components of the signalling pathway. This points to a potentially new mechanism of G-protein mediated signal transduction, the activation of a protein kinase through G beta gamma. |
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