title: Ssp1 CaMKK: A Sensor of Actin Polarization That Controls Mitotic Commitment through Srk1 in Schizosaccharomyces pombe.
abstract: BACKGROUND
  Calcium/calmodulin-dependent protein kinase kinase (CaMKK) is required for diverse cellular functions. Mammalian CaMKK activates CaMKs and also the evolutionarily-conserved AMP-activated protein kinase (AMPK). The fission yeast Schizosaccharomyces pombe CaMKK, Ssp1, is required for tolerance to limited glucose through the AMPK, Ssp2, and for the integration of cell growth and division through the SAD kinase Cdr2.
  
  
  RESULTS
  Here we report that Ssp1 controls the G2/M transition by regulating the activity of the CaMK Srk1. We show that inhibition of Cdc25 by Srk1 is regulated by Ssp1; and also that restoring growth polarity and actin localization of ssp1-deleted cells by removing the actin-monomer-binding protein, twinfilin, is sufficient to suppress the ssp1 phenotype.
  
  
  CONCLUSIONS
  These findings demonstrate that entry into mitosis is mediated by a network of proteins, including the Ssp1 and Srk1 kinases. Ssp1 connects the network of components that ensures proper polarity and cell size with the network of proteins that regulates Cdk1-cyclin B activity, in which Srk1 plays an inhibitory role.
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Gómez-Hierro
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Lambea
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Giménez-Zaragoza
authors.affiliation: The Biotechnology Centre of Oslo, Cell Cycle Regulation, Oslo, Norway.
authors.forename: Sandra
authors.initials: S
authors.lastname: López-Avilés
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: Tula
authors.initials: T
authors.lastname: Yance-Chávez
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Montserrat
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: M Jesús
authors.initials: MJ
authors.lastname: Pujol
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: Oriol
authors.initials: O
authors.lastname: Bachs
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalunya, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Aligue
mesh_terms: D000199:Actins / Q000378:metabolism*; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000502:physiology*; D050296:Microbial Viability; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008938:Mitosis; D009687:Nuclear Proteins / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism* / Q000502:physiology*
chemical_list: D000199:Actins; D018797:Cell Cycle Proteins; D018840:HSP70 Heat-Shock Proteins; D009687:Nuclear Proteins; C111935:PSS1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; C068689:wee1 protein, S pombe; D011505:Protein-Tyrosine Kinases; C499611:SRK1 protein, S pombe; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D020928:Mitogen-Activated Protein Kinases; C570820:Cdc25 protein, S pombe; D010749:Phosphoprotein Phosphatases