F. Banuett, SIGNALING IN THE YEASTS - AN INFORMATIONAL CASCADE WITH LINKS TO THE FILAMENTOUS FUNGI, Microbiology and molecular biology reviews, 62(2), 1998, pp. 249
All cells, from bacteria and yeasts to mammalian cells, respond to cue
s from their environment. A variety of mechanisms exist for the transd
uction of these external signals to the interior of the cell, resultin
g in altered patterns of protein activity. Eukaryotic cells commonly t
ransduce external cues via a conserved module composed of three protei
n kinases, the mitogen-activated protein kinase (MAPK) cascade. This m
odule can then activate substrates, some of which include transcriptio
nal activators. Multiple MAPK signalling pathways coexist in a cell. T
his review considers different MAPK cascade signalling pathways that g
overn several aspects of the life cycle of budding and fission yeasts:
conjugation and meiosis by the pheromone response pathway, stress res
ponse by the high-osmolarity and heat-sensing pathway, and pseudohypha
l growth in response to activation of a subset of the components of th
e pheromone response pathway. Because the MAPK cascade components are
highly conserved, a key question in studies of these pathways is the m
echanism by which specificity of response is achieved. Several other i
ssues to be addressed in this review concern the nature of the recepto
rs used to sense the external signals and the mechanism by which the r
eceptors communicate with other components leading to activation of th
e MAPK cascade. Recently, it has become apparent the MAPK cascades are
important in governing the pathogenicity of filamentous fungi.