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

• DOI: 10.1016/j.cub.2007.01.052
• Publication Date: 2007-02-16T12:23:05Z
• Authors: Pankaj Dhonukshe; Fernando Aniento; Inhwan Hwang; David G. Robinson; Jozef Mravec; York-Dieter Stierhof; Jiří Friml
• Keywords: PROTEINS; Recombinant Fusion Proteins; Arabidopsis; GRADIENTS; BREFELDIN-A; Plant Roots; 03 medical and health sciences; Genes, Reporter; TRANSFERRIN RECEPTOR; TRAFFICKING; PLANT-CELLS; 0303 health sciences; COMPLEX; Agricultural and Biological Sciences(all); Indoleacetic Acids; Biochemistry, Genetics and Molecular Biology(all); Arabidopsis Proteins; Protoplasts; Cell Membrane; Clathrin-Coated Vesicles; TRANSPORT; Clathrin; Endocytosis; Luminescent Proteins; FLUORESCENT MARKER; TYRPHOSTIN A23; CELLBIO

Endocytosis is an essential process by which eukaryotic cells internalize exogenous material or regulate signaling at the cell surface [1]. Different endocytic pathways are well established in yeast and animals; prominent among them is clathrin-dependent endocytosis [2, 3]. In plants, endocytosis is poorly defined, and no molecular mechanism for cargo internalization has been demonstrated so far [4, 5], although the internalization of receptor-ligand complexes at the plant plasma membrane has recently been shown [6]. Here we demonstrate by means of a green-to-red photoconvertible fluorescent reporter, EosFP [7], the constitutive endocytosis of PIN auxin efflux carriers [8] 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.