Figure 14.

A model for the function of Sbe2p and Sbe22p. We propose that Sbe2p and Sbe22p are part of the machinery that transports cell wall components to growth sites. By analogy with the well-known secretory pathway, Sbe2p and Sbe22p could be involved in the formation of secretory vesicles containing cell wall components such as mannoproteins or help to direct the fusion of these vesicles with the plasma membrane. This pathway is independent of the pathway involving Chs5p, which functions in the transport of Chs3p to the cell surface. Nevertheless, these two pathways may still be interconnected (see DISCUSSION).