Ssp1 CaMKK: A Sensor of Actin Polarization That Controls Mitotic Commitment through Srk1 in Schizosaccharomyces pombe

Alba Gómez-Hierro; Eva Lambea; David Giménez-Zaragoza; Sandra López-Avilés; Tula Yance-Chávez; Marta Montserrat; M Jesús Pujol; Oriol Bachs; Rosa Aligue

doi:10.1371/journal.pone.0143037

Ssp1 CaMKK: A Sensor of Actin Polarization That Controls Mitotic Commitment through Srk1 in Schizosaccharomyces pombe

PLoS One. 2015 Nov 17;10(11):e0143037. doi: 10.1371/journal.pone.0143037. eCollection 2015.

Authors

Alba Gómez-Hierro¹, Eva Lambea¹, David Giménez-Zaragoza¹, Sandra López-Avilés², Tula Yance-Chávez¹, Marta Montserrat¹, M Jesús Pujol¹, Oriol Bachs¹, Rosa Aligue¹

Affiliations

¹ 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.
² The Biotechnology Centre of Oslo, Cell Cycle Regulation, Oslo, Norway.

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Actins / metabolism*
Calcium-Calmodulin-Dependent Protein Kinase Kinase / metabolism*
Cell Cycle Proteins / metabolism
HSP70 Heat-Shock Proteins / physiology*
Microbial Viability
Mitogen-Activated Protein Kinases / metabolism*
Mitosis
Nuclear Proteins / metabolism
Phosphoprotein Phosphatases / metabolism
Phosphorylation
Protein-Tyrosine Kinases / metabolism
Schizosaccharomyces / cytology
Schizosaccharomyces / enzymology*
Schizosaccharomyces / growth & development
Schizosaccharomyces pombe Proteins / metabolism*
Schizosaccharomyces pombe Proteins / physiology*

Substances

Actins
Cell Cycle Proteins
HSP70 Heat-Shock Proteins
Nuclear Proteins
PSS1 protein, S pombe
Schizosaccharomyces pombe Proteins
wee1 protein, S pombe
Protein-Tyrosine Kinases
SRK1 protein, S pombe
Calcium-Calmodulin-Dependent Protein Kinase Kinase
Mitogen-Activated Protein Kinases
Cdc25 protein, S pombe
Phosphoprotein Phosphatases

Grants and funding

This work was supported by grants from the Spanish Ministry of Economy and Competitiveness (BFU2012-31220 to RA) and the Government of Catalonia (SRG2009-1526).