Title: | The Galpha subunit signals through the Ste50 protein during the mating pheromone response in the yeast Kluyveromyces lactis |
Author(s): | Sanchez-Paredes E; Kawasaki L; Ongay-Larios L; Coria R; |
Address: | "Departamento de Genetica Molecular, Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Mexico" |
ISSN/ISBN: | 1535-9786 (Electronic) 1535-9778 (Print) 1535-9786 (Linking) |
Abstract: | "Yeast mating signal transduction pathways require a heterotrimeric G protein composed of Galpha, Gbeta, and Ggamma subunits connected to a mitogen-activated protein kinase (MAPK) module. While in Saccharomyces cerevisiae elimination of Galpha induces constitutive activation of the mating pathway, in Kluyveromyces lactis it produces partial sterility, which indicates that K. lactis Galpha (KlGalpha) is required to positively activate mating. We use physical interaction experiments to determine that KlGalpha interacts with the adaptor protein KlSte50p. The Ras association (RA) domain of KlSte50p favored interaction with the GDP-bound KlGalpha subunit, and when the KlGalpha protein is constitutively activated, the interaction drops significantly. Additionally, KlSte50p strongly associates with the MAPK kinase kinase (MAPKKK) KlSte11p through its sterile alpha motif (SAM) domain. Genetic experiments placed KlSte50p downstream of the G protein alpha subunit, indicating that KlGalpha may stimulate the mating pathway via KlSte50p. Fusion of KlSte50p to the KlGbeta subunit partially eliminated the requirement of KlGalpha for mating, indicating that one contribution of KlGalpha to the mating pathway is to facilitate plasma membrane anchoring of KlSte50p" |
Keywords: | Amino Acid Sequence Base Sequence Fungal Proteins/genetics/*metabolism GTP-Binding Protein alpha Subunits/genetics/*metabolism Kluyveromyces/genetics/*physiology Molecular Sequence Data Pheromones/*metabolism Protein Subunits/genetics/metabolism Recombina; |
Notes: | "MedlineSanchez-Paredes, Edith Kawasaki, Laura Ongay-Larios, Laura Coria, Roberto eng Research Support, Non-U.S. Gov't 2011/02/22 Eukaryot Cell. 2011 Apr; 10(4):540-6. doi: 10.1128/EC.00285-10. Epub 2011 Feb 18" |