QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 20, Issue 18, 3996-4009, September 15, 2009

This Article Full Text Full Text (PDF) All Versions of this Article: E09-05-0388v1 20/18/3996    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Núñez, A. Articles by Cansado, J. PubMed PubMed Citation Articles by Núñez, A. Articles by Cansado, J.

Role for RACK1 Orthologue Cpc2 in the Modulation of Stress Response in Fission Yeast

Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, University of Murcia, 30071 Murcia, Spain

Submitted May 13, 2009; Revised July 2, 2009; Accepted July 9, 2009
Monitoring Editor: Daniel J. Lew

The receptor of activated C kinase (RACK1) is a protein highly conserved among eukaryotes. In mammalian cells, RACK1 functions as an adaptor to favor protein kinase C (PKC)-mediated phosphorylation and subsequent activation of c-Jun NH₂-terminal kinase mitogen-activated protein kinase. Cpc2, the RACK1 orthologue in the fission yeast Schizosaccharomyces pombe, is involved in the control of G2/M transition and interacts with Pck2, a PKC-type protein member of the cell integrity Pmk1 mitogen-activated protein kinase (MAPK) pathway. Both RACK1 and Cpc2 are structural components of the 40S ribosomal subunit, and recent data suggest that they might be involved in the control of translation. In this work, we present data supporting that Cpc2 negatively regulates the cell integrity transduction pathway by favoring translation of the tyrosine-phosphatases Pyp1 and Pyp2 that deactivate Pmk1. In addition, Cpc2 positively regulates the synthesis of the stress-responsive transcription factor Atf1 and the cytoplasmic catalase, a detoxificant enzyme induced by treatment with hydrogen peroxide. These results provide for the first time strong evidence that the RACK1-type Cpc2 protein controls from the ribosome the extent of the activation of MAPK cascades, the cellular defense against oxidative stress, and the progression of the cell cycle by regulating positively the translation of specific gene products involved in key biological processes.

* Present address: Paterson Institute for Cancer Research, University of Manchester, Manchester M20 4BX, United Kingdom.

Address correspondence to: Mariano Gacto (maga{at}um.es).

Abbreviations used: EMM2, Edinburgh minimal medium 2; GFP, green fluorescent protein; HA6H, epitope comprising hemagglutinin antigen plus six histidine residues; HA, hemagglutinin; MAPK, mitogen-activated protein kinase; PKC, protein kinase C; SAPK, stress-activated protein kinase; YES, yeast extract plus supplements.