454 / 2019-02-26 09:21:24

A positive feedback module on ROP-mediated self-organizing cell polarization

ROP GTPase, polarization, pollen tube, root hair, phosphorylation

全体主题 > Cell Biology

Self-organizing cell polarization is established and maintained by the asymmetric distribution of proteins and lipids. Pollen tubes and root hairs represent two types of self-organizing cell polarization in angiosperms, in which a single and unique growth axis is maintained to result in a cylindrical shape. Rho of Plants (ROP) represents the only Rho GTPases in plants, playing crucial roles in cell polarization. Here, we report a positive feedback module that is critical for ROP-mediated self-organizing cell polarization. Function loss of Arabidopsis AGC1.5 kinase compromised the tip growth of both pollen tubes and root hairs. AGC1.5 kinase interacts both with ROP activators and ROP signaling effectors, hinting at a role of AGC1.5 in the feedback control of ROP signaling. Indeed, AGC1.5 is recruited by ROP effectors to the active ROP domain, and phosphorylate RopGEFs to maintain the dynamic restriction of ROP signaling. Further evidence suggested that the oligomerization-phosphorylation positive feedback module may be a universal theme in self-organizing cell polarization in plants.