Nanodomain-mediated lateral sorting drives polarization of the small GTPase ROP2 in the plasma membrane of root hair cells

• DOI: 10.1101/2021.09.10.459822
• Publication Date: 2021-09-11T22:00:14Z
• Authors: Vanessa Aphaia Fi...; Philipp Denninger; Milan Župunski; Yvon Jaillais; Ulrike Engel; Guido Grossmann
• Keywords: Cell polarity

Formation of root hairs involves the targeted recruitment cellular growth machinery to hair initiation domain (RHID), a specialized site at plasma membrane (PM) trichoblast cells. Early determinants in RHID establishment are small GTPases Rho-of-plants (ROP) protein family, which required for polarization downstream effectors, modification and secretion during tip growth. It remains, however, not fully understood how ROP themselves polarized. To investigate mechanism underlying ROP2 recruitment, we employed Variable Angle Epifluorescence Microscopy (VAEM) exploited mCitrine fluorophore blinking single molecule localization, particle tracking super-resolved imaging membrane. We observed association mCit-ROP2 within distinct nanodomains, whose polar occurrence was dependent on presence RopGEF GEF3, found gradual, localized decrease mobility that preceded polarization. provide evidence step-wise model (i) an initial non-polar via interactions with anionic phospholipids, (ii) assembly into nanodomains independent nucleotide-binding state and, sub-sequently, (iii) lateral sorting RHID, driven by GEF3-mediated reduction mobility.