title: Functional identification of the phosphorylation sites of Arabidopsis PIN-FORMED3 for its subcellular localization and biological role.
abstract: Directional cell-to-cell movement of auxin is mediated by asymmetrically localized PIN-FORMED (PIN) auxin efflux transporters. The polar localization of PINs has been reported to be modulated by phosphorylation. In this study, the function of the phosphorylation sites of the PIN3 central hydrophilic loop (HL) was characterized. The phosphorylation sites were located in two conserved neighboring motifs, RKSNASRRSF(/L) and TPRPSNL, where the former played a more decisive role than the latter. Mutations of these phosphorylatable residues disrupted in planta phosphorylation of PIN3 and its subcellular trafficking, and caused defects in PIN3-mediated biological processes such as auxin efflux activity, auxin maxima formation, root growth, and root gravitropism. Because the defective intracellular trafficking behaviors of phospho-mutated PIN3 varied according to cell type, phosphorylation codes in PIN3-HL are likely to operate in a cell-type-specific manner.
authors.affiliation: Department of Biological Sciences and Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea.
authors.forename: Anindya
authors.initials: A
authors.lastname: Ganguly
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Hyung-Taeg
authors.initials: HT
authors.lastname: Cho
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002384:Catalysis; D018522:Gravitropism; D057927:Hydrophobic and Hydrophilic Interactions; D007210:Indoleacetic Acids / Q000378:metabolism*; D018519:Meristem / Q000502:physiology*; D008969:Molecular Sequence Data; D010766:Phosphorylation
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C449300:PIN3 protein, Arabidopsis