title: Polarized cell growth in Arabidopsis requires endosomal recycling mediated by GBF1-related ARF exchange factors.
abstract: Polarized tip growth is a fundamental cellular process in many eukaryotic organisms, mediating growth of neuronal axons and dendrites or fungal hyphae. In plants, pollen and root hairs are cellular model systems for analysing tip growth. Cell growth depends on membrane traffic. The regulation of this membrane traffic is largely unknown for tip-growing cells, in contrast to cells exhibiting intercalary growth. Here we show that in Arabidopsis, GBF1-related exchange factors for the ARF GTPases (ARF GEFs) GNOM and GNL2 play essential roles in polar tip growth of root hairs and pollen, respectively. When expressed from the same promoter, GNL2 (in contrast to the early-secretory ARF GEF GNL1) is able to replace GNOM in polar recycling of the auxin efflux regulator PIN1 from endosomes to the basal plasma membrane in non-tip growing cells. Thus, polar recycling facilitates polar tip growth, and GNL2 seems to have evolved to meet the specific requirement of fast-growing pollen in higher plants.
authors.affiliation: ZMBP, Entwicklungsgenetik, Universität Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Richter
authors.forename: Lena M
authors.initials: LM
authors.lastname: Müller
authors.forename: York-Dieter
authors.initials: YD
authors.lastname: Stierhof
authors.forename: Ulrike
authors.initials: U
authors.lastname: Mayer
authors.forename: Nozomi
authors.initials: N
authors.lastname: Takada
authors.forename: Benedikt
authors.initials: B
authors.lastname: Kost
authors.forename: Anne
authors.initials: A
authors.lastname: Vieten
authors.forename: Niko
authors.initials: N
authors.lastname: Geldner
authors.forename: Csaba
authors.initials: C
authors.lastname: Koncz
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
mesh_terms: D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D016764:Cell Polarity / Q000235:genetics / Q000502:physiology*; D011992:Endosomes / Q000235:genetics / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D011058:Pollen / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C552546:GBF1 protein, Arabidopsis; C553229:GNL protein, Arabidopsis; C088087:GNOM protein, Arabidopsis; D020662:Guanine Nucleotide Exchange Factors; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D014157:Transcription Factors; D020727:ADP-Ribosylation Factors