The mating-specific Galpha interacts with a kinesin-14 and regulates pheromone-induced nuclear migration in budding yeast.
As a budding yeast cell elongates toward its mating partner, cytoplasmic microtubules connect the nucleus to the cell cortex at the growth tip. The Kar3 kinesin-like motor protein is then thought to stimulate plus-end depolymerization of these microtubules, thus drawing the nucleus closer to the site where cell fusion and karyogamy will occur. Here, we show that pheromone stimulates a microtubule-independent interaction between Kar3 and the mating-specific Galpha protein Gpa1 and that Gpa1 affects both microtubule orientation and cortical contact. The membrane localization of Gpa1 was found to polarize early in the mating response, at about the same time that the microtubules begin to attach to the incipient growth site. In the absence of Gpa1, microtubules lose contact with the cortex upon shrinking and Kar3 is improperly localized, suggesting that Gpa1 is a cortical anchor for Kar3. We infer that Gpa1 serves as a positional determinant for Kar3-bound microtubule plus ends during mating.
Zaichick
Sofia V
SV
Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
Metodiev
Metodi V
MV
Nelson
Scott A
SA
Durbrovskyi
Oleksii
O
Draper
Edward
E
Cooper
John A
JA
Stone
David E
DE
D000199:Actins / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D016764:Cell Polarity / Q000187:drug effects; D036681:Fluorescence Recovery After Photobleaching; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000172:deficiency / Q000378:metabolism*; D049770:Genes, Mating Type, Fungal; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008868:Microtubule Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D010675:Pheromones / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
D000199:Actins; C076025:CIK1 protein, S cerevisiae; C063504:KAR3 protein, S cerevisiae; D008868:Microtubule Proteins; D008869:Microtubule-Associated Proteins; D010675:Pheromones; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; C084293:GPA1 protein, S cerevisiae; D043802:GTP-Binding Protein alpha Subunits, Gq-G11