title: Regulation of Rho-GEF Rgf3 by the arrestin Art1 in fission yeast cytokinesis.
abstract: Rho GTPases, activated by guanine nucleotide exchange factors (GEFs), are essential regulators of polarized cell growth, cytokinesis, and many other cellular processes. However, the regulation of Rho-GEFs themselves is not well understood. Rgf3 is an essential GEF for Rho1 GTPase in fission yeast. We show that Rgf3 protein levels and localization are regulated by arrestin-related protein Art1. art1∆ cells lyse during cell separation with a thinner and defective septum. As does Rgf3, Art1 concentrates to the contractile ring starting at early anaphase and spreads to the septum during and after ring constriction. Art1 localization depends on its C-terminus, and Art1 is important for maintaining Rgf3 protein levels. Biochemical experiments reveal that the Rgf3 C-terminus binds to Art1. Using an Rgf3 conditional mutant and mislocalization experiments, we found that Art1 and Rgf3 are interdependent for localization to the division site. As expected, active Rho1 levels at the division site are reduced in art1∆ and rgf3 mutant cells. Taken together, these data reveal that the arrestin family protein Art1 regulates the protein levels and localization of the Rho-GEF Rgf3, which in turn modulates active Rho1 levels during fission yeast cytokinesis.
authors.affiliation: Graduate Program of Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH 43210 Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
authors.forename: Reshma
authors.initials: R
authors.lastname: Davidson
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
authors.forename: Damien
authors.initials: D
authors.lastname: Laporte
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210 wu.620@osu.edu.
authors.forename: Jian-Qiu
authors.initials: JQ
authors.lastname: Wu
mesh_terms: D000705:Anaphase / Q000502:physiology; D019390:Arrestins / Q000737:chemistry / Q000378:metabolism*; D048749:Cytokinesis / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D012568:Schizosaccharomyces / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D019390:Arrestins; C000601537:Art1 protein, S pombe; D020662:Guanine Nucleotide Exchange Factors; C502214:Rgf3 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D020741:rho GTP-Binding Proteins; C511156:rho1 protein, S pombe