title: ROP GTPase-dependent actin microfilaments promote PIN1 polarization by localized inhibition of clathrin-dependent endocytosis.
abstract: Cell polarization via asymmetrical distribution of structures or molecules is essential for diverse cellular functions and development of organisms, but how polarity is developmentally controlled has been poorly understood. In plants, the asymmetrical distribution of the PIN-FORMED (PIN) proteins involved in the cellular efflux of the quintessential phytohormone auxin plays a central role in developmental patterning, morphogenesis, and differential growth. Recently we showed that auxin promotes cell interdigitation by activating the Rho family ROP GTPases in leaf epidermal pavement cells. Here we found that auxin activation of the ROP2 signaling pathway regulates the asymmetric distribution of PIN1 by inhibiting its endocytosis. ROP2 inhibits PIN1 endocytosis via the accumulation of cortical actin microfilaments induced by the ROP2 effector protein RIC4. Our findings suggest a link between the developmental auxin signal and polar PIN1 distribution via Rho-dependent cytoskeletal reorganization and reveal the conservation of a design principle for cell polarization that is based on Rho GTPase-mediated inhibition of endocytosis.
authors.affiliation: Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America.
authors.forename: Shingo
authors.initials: S
authors.lastname: Nagawa
authors.forename: Tongda
authors.initials: T
authors.lastname: Xu
authors.forename: Deshu
authors.initials: D
authors.lastname: Lin
authors.forename: Pankaj
authors.initials: P
authors.lastname: Dhonukshe
authors.forename: Xingxing
authors.initials: X
authors.lastname: Zhang
authors.forename: Jiri
authors.initials: J
authors.lastname: Friml
authors.forename: Ben
authors.initials: B
authors.lastname: Scheres
authors.forename: Ying
authors.initials: Y
authors.lastname: Fu
authors.forename: Zhenbiao
authors.initials: Z
authors.lastname: Yang
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D016764:Cell Polarity; D002966:Clathrin / Q000378:metabolism*; D004705:Endocytosis; D019204:GTP-Binding Proteins / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D009024:Morphogenesis; D019441:Plant Epidermis / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D014026:Nicotiana / Q000166:cytology / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D002966:Clathrin; D019204:GTP-Binding Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; C116363:PIN1 protein, Arabidopsis; C499716:RIC4 protein, Arabidopsis; C499714:AT1G20090 protein, Arabidopsis