title: Salicylic acid interferes with clathrin-mediated endocytic protein trafficking.
abstract: Removal of cargos from the cell surface via endocytosis is an efficient mechanism to regulate activities of plasma membrane (PM)-resident proteins, such as receptors or transporters. Salicylic acid (SA) is an important plant hormone that is traditionally associated with pathogen defense. Here, we describe an unanticipated effect of SA on subcellular endocytic cycling of proteins. Both exogenous treatments and endogenously enhanced SA levels repressed endocytosis of different PM proteins. The SA effect on endocytosis did not involve transcription or known components of the SA signaling pathway for transcriptional regulation. SA likely targets an endocytic mechanism that involves the coat protein clathrin, because SA interfered with the clathrin incidence at the PM and clathrin-deficient mutants were less sensitive to the impact of SA on the auxin distribution and root bending during the gravitropic response. By contrast, SA did not affect the ligand-induced endocytosis of the flagellin sensing2 (FLS2) receptor during pathogen responses. Our data suggest that the established SA impact on transcription in plant immunity and the nontranscriptional effect of SA on clathrin-mediated endocytosis are independent mechanisms by which SA regulates distinct aspects of plant physiology.
authors.affiliation: Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Du
authors.forename: Ricardo
authors.initials: R
authors.lastname: Tejos
authors.forename: Martina
authors.initials: M
authors.lastname: Beck
authors.forename: Ellie
authors.initials: E
authors.lastname: Himschoot
authors.forename: Hongjiang
authors.initials: H
authors.lastname: Li
authors.forename: Silke
authors.initials: S
authors.lastname: Robatzek
authors.forename: Steffen
authors.initials: S
authors.lastname: Vanneste
authors.forename: Jirí
authors.initials: J
authors.lastname: Friml
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D018522:Gravitropism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal / Q000379:methods; D057865:Plant Immunity; D018517:Plant Roots / Q000166:cytology; D021381:Protein Transport; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D002966:Clathrin; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D049452:Green Fluorescent Proteins; D020156:Salicylic Acid