Since plant cells are enclosed in a rigid cell wall, they cannot migrate. All plant mophogenesis, both on the level of a single cell and on the multicellular body level, must thus be accomplished by oriented cell division and polarized cell growth. Both of these processes are critically dependent on the cells´ ability to deliver compounds and structures (such as, e.g., secretory vesicles) to distinct parts of its surface (or distinct intracellular compartments). Polarized exocytosis is also unseparable from membrane recycling, and thus from the context of the whole endomembrane system.
The image (from ®árský et al. 2009) presents a summary of known signalling proteins participating in the establishment and function of an activated cortical domain (ACD) - an area of the cell surface engaged in active membrane turnover.
