title: Spatial landmarks regulate a Cdc42-dependent MAPK pathway to control differentiation and the response to positional compromise.
abstract: A fundamental problem in cell biology is to understand how spatial information is recognized and integrated into morphogenetic responses. Budding yeast undergoes differentiation to filamentous growth, which involves changes in cell polarity through mechanisms that remain obscure. Here we define a regulatory input where spatial landmarks (bud-site-selection proteins) regulate the MAPK pathway that controls filamentous growth (fMAPK pathway). The bud-site GTPase Rsr1p regulated the fMAPK pathway through Cdc24p, the guanine nucleotide exchange factor for the polarity establishment GTPase Cdc42p. Positional landmarks that direct Rsr1p to bud sites conditionally regulated the fMAPK pathway, corresponding to their roles in regulating bud-site selection. Therefore, cell differentiation is achieved in part by the reorganization of polarity at bud sites. In line with this conclusion, dynamic changes in budding pattern during filamentous growth induced corresponding changes in fMAPK activity. Intrinsic compromise of bud-site selection also impacted fMAPK activity. Therefore, a surveillance mechanism monitors spatial position in response to extrinsic and intrinsic stress and modulates the response through a differentiation MAPK pathway.
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Sukanya
authors.initials: S
authors.lastname: Basu
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Nadia
authors.initials: N
authors.lastname: Vadaie
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Aditi
authors.initials: A
authors.lastname: Prabhakar
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Boyang
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Hema
authors.initials: H
authors.lastname: Adhikari
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Andrew
authors.initials: A
authors.lastname: Pitoniak
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Jacky
authors.initials: J
authors.lastname: Chow
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Chavel
authors.affiliation: Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260 pjcullen@buffalo.edu.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Cullen
mesh_terms: D020935:MAP Kinase Signaling System; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae
keywords: GTPase; MAPK; polar landmarks; polarity establishment; spatial cues