title: Phosphorylation of Bni4 by MAP kinases contributes to septum assembly during yeast cytokinesis.
abstract: Previous work has shown that the synthetic lethality of the slt2Δrim101Δ mutant results from a combination of factors, including improper functioning of the septum assembly machinery. Here, we identify new multicopy suppressors of this lethality including Kss1, Pcl1 and Sph1, none of which seems to be linked to the upregulation of chitin synthesis. Characterization of the suppression mediated by Kss1 showed that it is independent of the transcriptional response of the CWI signaling response, but efficiently restores the Bni4 localization defects produced by the absence of Slt2. Accordingly, Bni4 interacts physically with both kinases, and its levels of phosphorylation are reduced in the slt2Δ mutant but increased after Kss1 overexpression. Using an assay based on hypersensitive cells of the cdc10-11 mutant, we have pinpointed several MAP kinase phosphorylatable residues required for Bni4 function. Our results, together with a genetic correlation analysis, strongly support a functional model linking Slt2 MAP kinase and Pcl1, a Pho85 cyclin-dependent kinase, in septum assembly through Bni4. This model, based on the coordinated phosphorylation of Bni4 by both kinases, would be able to integrate cellular signals rapidly to maintain cell integrity during cytokinesis.
authors.affiliation: IBFG and Departamento de Microbiología and Genética, CSIC/Universidad de Salamanca, IBFG, Salamanca, 37007, Spain.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Pérez
authors.affiliation: IBFG and Departamento de Microbiología and Genética, CSIC/Universidad de Salamanca, IBFG, Salamanca, 37007, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Arcones
authors.affiliation: IBFG and Departamento de Microbiología and Genética, CSIC/Universidad de Salamanca, IBFG, Salamanca, 37007, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Gómez
authors.affiliation: IBFG and Departamento de Microbiología and Genética, CSIC/Universidad de Salamanca, IBFG, Salamanca, 37007, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: Casquero
authors.affiliation: IBFG and Departamento de Microbiología and Genética, CSIC/Universidad de Salamanca, IBFG, Salamanca, 37007, Spain crm@usal.es.
authors.forename: César
authors.initials: C
authors.lastname: Roncero
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism*; D048749:Cytokinesis; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: C494956:Bni4p protein, S cerevisiae; D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D010738:Type C Phospholipases; C522285:Plc1 protein, S cerevisiae
keywords: MAP kinase; cytokinesis; septum assembly