The Bud14p-Glc7p complex functions as a cortical regulator of dynein in budding yeast.
Regulated interactions between microtubules (MTs) and the cell cortex control MT dynamics and position the mitotic spindle. In eukaryotic cells, the adenomatous polyposis coli/Kar9p and dynein/dynactin pathways are involved in guiding MT plus ends and MT sliding along the cortex, respectively. Here we identify Bud14p as a novel cortical activator of the dynein/dynactin complex in budding yeast. Bud14p accumulates at sites of polarized growth and the mother-bud neck during cytokinesis. The localization to bud and shmoo tips requires an intact actin cytoskeleton and the kelch-domain-containing proteins Kel1p and Kel2p. While cells lacking Bud14p function fail to stabilize the pre-anaphase spindle at the mother-bud neck, overexpression of Bud14p is toxic and leads to elongated astral MTs and increased dynein-dependent sliding along the cell cortex. Bud14p physically interacts with the type-I phosphatase Glc7p, and localizes Glc7p to the bud cortex. Importantly, the formation of Bud14p-Glc7p complexes is necessary to regulate MT dynamics at the cortex. Taken together, our results suggest that Bud14p functions as a regulatory subunit of the Glc7p type-I phosphatase to stabilize MT interactions specifically at sites of polarized growth.
Knaus
Michèle
M
Swiss Federal Institute of Technology Zürich (ETH), Institute of Biochemistry, Zürich, Switzerland.
Cameroni
Elisabetta
E
Pedruzzi
Ivo
I
Tatchell
Kelly
K
De Virgilio
Claudio
C
Peter
Matthias
M
D008841:Actin Cytoskeleton / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D002352:Carrier Proteins / Q000378:metabolism; D017124:Conserved Sequence; D048749:Cytokinesis; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D054645:Protein Phosphatase 1; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus
D048868:Adaptor Proteins, Signal Transducing; C474555:Bud14 protein, S cerevisiae; D002352:Carrier Proteins; D000072159:Dynactin Complex; C489835:KEL1 protein, S cerevisiae; C489836:KEL2 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; C092048:GLC7 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D004398:Dyneins