Actin-driven polar growth of plant cells

Abstract

One of the major discoveries in cell biology from the past decade was the finding that forces associated with actin polymerization are strong enough to propel bacteria such as Listeria and Shigella within eukaryotic host cells and even to drive animal/mammalian cell motility by pushing the plasma membrane at their advancing fronts. This actin polymerization-driven ‘pushing of the cellular envelope’ is tightly coupled to both signal-perception and signal transduction at the plasma membrane. The coupling of signaling at the plasma membrane to actin dynamics is valid also for plant cells [1,2]. However, until recently, plant cells did not seem to fit into the emerging scheme in which the dynamic machinery associated with the process of actin polymerization is implicated in signaling-mediated navigation required for cell polarity and motility. Obviously, this might have something to do with the unique features of plant cells – which are all enclosed by rigid cell walls. The latter feature precludes cellular motility, and a long-standing dogma holds that the ultimate force behind cellular growth in plant cells is the high internal turgor pressure generated within plant cells.