Figure 1.

Schematic representation of the key events in cell wall biosynthesis. Cellulose biosynthesis occurs at the plasma membrane in large complexes visualized as rosettes. The synthesis of matrix polysaccharides and glycoproteins occurs in the Golgi where the products accumulate in the lumen before transport to the cell wall via vesicles. The regulation of these biosynthetic events is an important issue that needs more study. Abbreviations used in the figure: CesA, cellulose synthase proteins that form the rosette; NDP-sugar, nucleotide sugars that act as donors for the sugars that go into polysaccharides; Csl, cellulose synthase-like proteins that are known to be involved in hemicellulose biosynthesis.