title: Pob1 ensures cylindrical cell shape by coupling two distinct rho signaling events during secretory vesicle targeting.
abstract: Proper cell morphogenesis requires the co-ordination of cell polarity, cytoskeletal organization and vesicle trafficking. The Schizosaccharomyces pombe mutant pob1-664 has a curious lemon-like shape, the basis of which is not understood. Here, we found abundant vesicle accumulation in these cells, suggesting that Pob1 plays a role in vesicle trafficking. We identified Rho3 as a multicopy suppressor of this phenotype. Because Rho3 function is related to For3, an actin-polymerizing protein, and Sec8, a component of the exocyst complex, we analyzed their functional relationship with Pob1. Pob1 was essential for the formation of actin cables (by interacting with For3) and for the polarized localization of Sec8. Although neither For3 nor Sec8 is essential for polarized growth, their simultaneous disruption prevented tip growth and yielded a lemon-like cell morphology similar to pob1-664. Thus, Pob1 may ensure cylindrical cell shape of S. pombe by coupling actin-mediated vesicle transport and exocyst-mediated vesicle tethering during secretory vesicle targeting.
authors.affiliation: Department of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan. knakano@biol.tsukuba.ac.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nakano
authors.forename: Mika
authors.initials: M
authors.lastname: Toya
authors.forename: Aki
authors.initials: A
authors.lastname: Yoneda
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Asami
authors.forename: Akira
authors.initials: A
authors.lastname: Yamashita
authors.forename: Naomi
authors.initials: N
authors.lastname: Kamasawa
authors.forename: Masako
authors.initials: M
authors.lastname: Osumi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000199:Actins / Q000378:metabolism / Q000648:ultrastructure; D018797:Cell Cycle Proteins / Q000378:metabolism; D048430:Cell Shape; D000080865:Formins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism*; D015398:Signal Transduction; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D018797:Cell Cycle Proteins; C444419:FOR3 protein, S pombe; D000080865:Formins; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C489566:rho3 protein, S pombe; C548057:Pob1 protein, S pombe; D020741:rho GTP-Binding Proteins