Signalling towards cell wall synthesis in budding yeast.
The budding yeast Saccharomyces cerevisiae has long proved to be a very useful model in cell biology. Its cell morphology is established and maintained at least in part by the cell wall, a rigid but dynamic structure that affords mechanical protection. Although fungal cell walls represent an unique phenomenon, recent progress in research has shown striking parallels between yeast and mammalian cells in the area of cell morphogenesis and proliferation. Further studies promise to shed common light on the processes of cell morphogenesis including the intersections with proliferation control. This review focuses on the recent progress in this promising area in the yeast Saccharomyces cerevisiae. The process of cell wall synthesis in Saccharomyces cerevisiae was reviewed by several authors recently. Briefly, the cell wall represents a complex structure of cross-linked chitin, beta-(1,6)-d-glucan, beta-(1,3)-D-glucan and mannoproteins. Chitin and beta-(1,3)-D-glucan are synthesized by enzymatic complexes at the cell membrane and extruded into the periplasmic space, mannoproteins are synthesized along the yeast secretory pathway, and the site of beta-(1,6)-D-glucan synthesis is still unknown. The principal motif which interconnects individual cell wall constituents was recently identified by Kollár et al. The mechanisms of cross-linking of the polymers in the wall remain unknown, however. Recently, nevertheless, substantial progress has been achieved in understanding the signalling pathways which target the cell wall construction.