title: Different Endomembrane Trafficking Pathways Establish Apical and Basal Polarities.
abstract: The endomembrane system is an interconnected network required to establish signal transduction, cell polarity, and cell shape in response to developmental or environmental stimuli. In the model plantArabidopsis thaliana, there are numerous markers to visualize polarly localized plasma membrane proteins utilizing endomembrane trafficking. Previous studies have shown that the large ARF-GEF GNOM plays a key role in the establishment of basal (rootward) polarity, whereas the apically (shootward) polarized membrane proteins undergo sorting via different routes. However, the mechanism that maintains apical polarity is largely unknown. Here, we used a chemical genomic approach and identified the compound endosidin 16 (ES16), which perturbed apically localized plasma membrane proteins without affecting basal polarity. We demonstrated that ES16 is an inhibitor for recycling of apical, lateral, and nonpolar plasma membrane proteins as well as biosynthetic secretion, leaving the basal proteins as the only exceptions not subject to ES16 inhibition. Further evidence from pharmaceutical and genetic data revealed that ES16 effects are mediated through the regulation of small GTPase RabA proteins and that RabA GTPases work in concert with the BIG clade ARF-GEF to modulate the nonbasal trafficking. Our results reveal that ES16 defines a distinct pathway for endomembrane sorting routes and is essential for the establishment of cell polarity.
authors.affiliation: Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California 92521.|Department of Botany and Plant Sciences, University of California, Riverside, California 92521.|Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China.
authors.forename: Ruixi
authors.identifier: 0000-0001-6288-6204
authors.initials: R
authors.lastname: Li
authors.affiliation: Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California 92521.|Department of Botany and Plant Sciences, University of California, Riverside, California 92521.
authors.forename: Cecilia
authors.identifier: 0000-0002-3453-4719
authors.initials: C
authors.lastname: Rodriguez-Furlan
authors.affiliation: Shenzhen Key Laboratory of Cell Microenvironment, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China.
authors.forename: Junqi
authors.identifier: 0000-0002-4774-0263
authors.initials: J
authors.lastname: Wang
authors.affiliation: Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California 92521.|Department of Botany and Plant Sciences, University of California, Riverside, California 92521.
authors.forename: Wilhelmina
authors.initials: W
authors.lastname: van de Ven
authors.affiliation: Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China.
authors.forename: Ting
authors.identifier: 0000-0003-4889-0113
authors.initials: T
authors.lastname: Gao
authors.affiliation: Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California 92521.|Department of Botany and Plant Sciences, University of California, Riverside, California 92521.
authors.forename: Natasha V
authors.initials: NV
authors.lastname: Raikhel
authors.affiliation: Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California 92521 ghicks@ucr.edu.|Department of Botany and Plant Sciences, University of California, Riverside, California 92521.
authors.forename: Glenn R
authors.identifier: 0000-0002-2502-7782
authors.initials: GR
authors.lastname: Hicks
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D016764:Cell Polarity / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000187:drug effects; D015363:Quinolones / Q000737:chemistry / Q000494:pharmacology; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; C088087:GNOM protein, Arabidopsis; D020662:Guanine Nucleotide Exchange Factors; D015363:Quinolones; C000624951:endosidin 16; C586737:Rab GTPase 11C, Arabidopsis thaliana; D020691:rab GTP-Binding Proteins