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Clathrin-Mediated Constitutive Endocytosis of PIN Auxin Efflux Carriers in Arabidopsis

2007; Elsevier BV; Volume: 17; Issue: 6 Linguagem: Inglês

10.1016/j.cub.2007.01.052

1879-0445

Pankaj Dhonukshe, Fernando Aniento, Inhwan Hwang, David G. Robinson, Jozef Mravec, York‐Dieter Stierhof, Jìří Friml,

Cellular transport and secretion

Endocytosis is an essential process by which eukaryotic cells internalize exogenous material or regulate signaling at the cell surface [1Alberts B. Johnson A. Lewis J. Raff M. Roberts K. Walter P. Molecular Biology of the Cell.4th Edition. Garland Science, New York2002Google Scholar]. Different endocytic pathways are well established in yeast and animals; prominent among them is clathrin-dependent endocytosis [2Conner S.D. Schmid S.L. Regulated portals of entry into the cell.Nature. 2003; 422: 37-44Crossref PubMed Scopus (2848) Google Scholar, 3Kirchhausen T. Clathrin.Annu. Rev. Biochem. 2000; 69: 699-727Crossref PubMed Scopus (479) Google Scholar]. In plants, endocytosis is poorly defined, and no molecular mechanism for cargo internalization has been demonstrated so far [4Murphy A.S. Bandyopadhyay A. Holstein S.E. Peer W.A. Endocytotic cycling of PM proteins.Annu. Rev. Plant Biol. 2005; 56: 221-251Crossref PubMed Scopus (132) Google Scholar, 5Russinova E. de Vries S.C. Receptor-mediated endocytosis in plants.in: Samaj J. Baluska F. Menzel D. Plant Endocytosis. Volume 1. Springer Verlag, Heidelberg2005: 103-115Google Scholar], although the internalization of receptor-ligand complexes at the plant plasma membrane has recently been shown [6Robatzek S. Chinchilla D. Boller T. Ligand-induced endocytosis of the pattern recognition receptor FLS2 in Arabidopsis.Genes Dev. 2006; 20: 537-542Crossref PubMed Scopus (520) Google Scholar]. Here we demonstrate by means of a green-to-red photoconvertible fluorescent reporter, EosFP [7Wiedenmann J. Ivanchenko S. Oswald F. Schmitt F. Rocker C. Salih A. Spindler K.D. Nienhaus G.U. EosFP, a fluorescent marker protein with UV-inducible green-to-red fluorescence conversion.Proc. Natl. Acad. Sci. USA. 2004; 101: 15905-15910Crossref PubMed Scopus (538) Google Scholar], the constitutive endocytosis of PIN auxin efflux carriers [8Petrasek J. Mravec J. Bouchard R. Blakeslee J.J. Abas M. Seifertova D. Wisniewska J. Tadele Z. Kubes M. Covanova M. et al.PIN proteins perform a rate-limiting function in cellular auxin efflux.Science. 2006; 312: 914-918Crossref PubMed Scopus (657) Google Scholar] and their recycling to the plasma membrane. Using a plant clathrin-specific antibody, we show the presence of clathrin at different stages of coated-vesicle formation at the plasma membrane in Arabidopsis. Genetic interference with clathrin function inhibits PIN internalization and endocytosis in general. Furthermore, pharmacological interference with cargo recruitment into the clathrin pathway blocks internalization of PINs and other plasma-membrane proteins. Our data demonstrate that clathrin-dependent endocytosis is operational in plants and constitutes the predominant pathway for the internalization of numerous plasma-membrane-resident proteins including PIN auxin efflux carriers.