title: Arabidopsis AIP1-2 restricted by WER-mediated patterning modulates planar polarity.
abstract: The coordination of cell polarity within the plane of the tissue layer (planar polarity) is crucial for the development of diverse multicellular organisms. Small Rac/Rho-family GTPases and the actin cytoskeleton contribute to planar polarity formation at sites of polarity establishment in animals and plants. Yet, upstream pathways coordinating planar polarity differ strikingly between kingdoms. In the root of Arabidopsis thaliana, a concentration gradient of the phytohormone auxin coordinates polar recruitment of Rho-of-plant (ROP) to sites of polar epidermal hair initiation. However, little is known about cytoskeletal components and interactions that contribute to this planar polarity or about their relation to the patterning machinery. Here, we show that ACTIN7 (ACT7) represents a main actin isoform required for planar polarity of root hair positioning, interacting with the negative modulator ACTIN-INTERACTING PROTEIN1-2 (AIP1-2). ACT7, AIP1-2 and their genetic interaction are required for coordinated planar polarity of ROP downstream of ethylene signalling. Strikingly, AIP1-2 displays hair cell file-enriched expression, restricted by WEREWOLF (WER)-dependent patterning and modified by ethylene and auxin action. Hence, our findings reveal AIP1-2, expressed under control of the WER-dependent patterning machinery and the ethylene signalling pathway, as a modulator of actin-mediated planar polarity.
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Christian S
authors.initials: CS
authors.lastname: Kiefer
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Andrea R
authors.initials: AR
authors.lastname: Claes
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Nzayisenga
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pietra
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Stanislas
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Anke
authors.initials: A
authors.lastname: Hüser
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå SE-90 187, Sweden Institute of Biochemistry and Biology, Plant Physiology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm D-14476, Germany markus.grebe@uni-potsdam.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Grebe
mesh_terms: D000199:Actins / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology* / Q000196:embryology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D019521:Body Patterning; D002352:Carrier Proteins / Q000378:metabolism*; D016764:Cell Polarity; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004843:Epistasis, Genetic; D005030:Ethylenes / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D015398:Signal Transduction
chemical_list: C000595350:AIP1-2 protein, Arabidopsis; D000199:Actins; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D005030:Ethylenes; C402111:WER protein, Arabidopsis; C036216:ethylene
keywords: AIP1; Actin; Arabidopsis; Patterning; Planar polarity; WEREWOLF