The fission yeast cell wall stress sensor-like proteins Mtl2 and Wsc1 act by turning on the GTPase Rho1p but act independently of the cell wall integrity pathway
Article first published online: 30 JUL 2013
© 2013 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 2, Issue 5, pages 778–794, October 2013
How to Cite
MicrobiologyOpen 2013; 2(5): 778–794
- Issue published online: 8 OCT 2013
- Article first published online: 30 JUL 2013
- Manuscript Accepted: 11 JUN 2013
- Manuscript Revised: 7 JUN 2013
- Manuscript Received: 22 APR 2013
- CICYT. Grant Numbers: BFU2008-00963/BMC, BFU2011-24683/BMC
- Junta de Castilla y León. Grant Number: GR231
- Ramón Areces Foundation
- Cell wall;
- cell wall sensor;
- fission yeast;
- MAPK pathway;
Sensing stressful conditions that affect the cell wall reorganization is important for yeast survival. Here, we studied two proteins SpWsc1p and SpMtl2p with structural features indicative of plasma membrane-associated cell wall sensors. We found that Mtl2p and Wsc1p act by turning on the Rho1p GTPase. Each gene could be deleted individually without affecting viability, but the deletion of both was lethal and this phenotype was rescued by overexpression of the genes encoding either Rho1p or its GDP/GTP exchange factors (GEFs). In addition, wsc1Δ and mtl2Δ cells showed a low level of Rho1p-GTP under cell wall stress. Mtl2p-GFP (green fluorescent protein) localized to the cell periphery and was necessary for survival under different types of cell wall stress. Wsc1p-GFP was concentrated in patches at the cell tips, it interacted with the Rho-GEF Rgf2p, and its overexpression activated cell wall biosynthesis. Our results are consistent with the notion that cell wall assembly is regulated by two different networks involving Rho1p. One includes signaling from Mtl2p through Rho1p to Pck1p, while the second one implicates signaling from Wsc1p and Rgf2p through Rho1p to activate glucan synthase (GS). Finally, signaling through the mitogen-activated protein kinase (MAPK) Pmk1p remained active in mtl2Δ and wsc1Δ disruptants exposed to cell wall stress, suggesting that the cell wall stress-sensing spectrum of Schizosaccharomyces pombe sensor-like proteins differs from that of Saccharomyces cerevisiae.