Cell integrity signaling and response to stress in fission yeast.

Cellular responses to external signals are regulated by conserved mitogen-activated protein (MAP) kinase signaling cascades. These pathways are triggered by a vast range of stimuli. They phosphorylate numerous proteins, produce significant changes in the gene expression, and regulate diverse processes ranging from proliferation and differentiation to apoptosis in all eukaryotic cells. Three conserved MAP kinase signaling pathways have been identified in the fission yeast Schizosaccharomyces pombe. In this article, we present an overview of two of those pathways that regulate the response of fission yeast to stress and maintain cell integrity. The structure of these signaling modules and the function of the pathways, including the regulation by endogenous inhibitors, are discussed.