Fungal cell wall synthesis: the construction of a biological structure.

The cell wall is of vital importance for the protection of the fungal cell. It consists of structural components, mostly beta-linked polysaccharides, and of interstitial components, usually glycoproteins. Cell shape is determined by the wall and is attained by localized growth. Regulatory mechanisms that act on chitin and beta(1----3) glucan synthetase indicate how localized biosynthesis can be achieved. Whereas structural polysaccharides appear to be exported by vectorial synthesis through the plasma membrane, glycoproteins are manufactured in an assembly line that takes them through several cellular compartments before exocytosis to the periplasmic space. In this space, the last phase of cell wall construction takes place, i.e. branching of structural polysaccharides and linkage between different components.