ABP1 Mediates Auxin Inhibition of Clathrin-Dependent Endocytosis in Arabidopsis

SummarySpatial distribution of the plant hormone auxin regulates multiple aspects of plant development. These self-regulating auxin gradients are established by the action of PIN auxin transporters, whose activity is regulated by their constitutive cycling between the plasma membrane and endosomes. Here, we show that auxin signaling by the auxin receptor AUXIN-BINDING PROTEIN 1 (ABP1) inhibits the clathrin-mediated internalization of PIN proteins. ABP1 acts as a positive factor in clathrin recruitment to the plasma membrane, thereby promoting endocytosis. Auxin binding to ABP1 interferes with this action and leads to the inhibition of clathrin-mediated endocytosis. Our study demonstrates that ABP1 mediates a nontranscriptional auxin signaling that regulates the evolutionarily conserved process of clathrin-mediated endocytosis and suggests that this signaling may be essential for the developmentally important feedback of auxin on its own transport.

Graphical AbstractFigure optionsDownload full-size imageDownload high-quality image (206 K)Download as PowerPoint slideHighlights► Auxin inhibits clathrin-dependent endocytosis rapidly and independently of TIR-1 ► AUXIN-BINDING PROTEIN 1 (ABP1) positively regulates clathrin-dependent endocytosis ► Auxin binds to ABP1 and inhibits clathrin-mediated endocytosis ► Control of endocytosis modulates the cell surface availability of PIN1