O-GlcNAc transferase modulates formation of clathrin-coated pits

Abstract

Clathrin-mediated endocytosis (CME) controls the internalization and function of a wide range of cell surface proteins. CME occurs by the assembly of clathrin and many other proteins on the inner leaflet of the plasma membrane into clathrin-coated pits (CCPs). These structures recruit specific membrane protein cargo destined for internalization and trigger the generation of membrane curvature that precedes eventual scission of CCPs from the plasma membrane to yield intracellular vesicles. The diversity of cell surface protein cargo thus controlled by CME indicates that CCP formation is regulated to allow cellular adaptation under different contexts. Of interest is how cues derived from cellular metabolism may regulate CME, given the reciprocal role of CME in controlling cellular metabolism. The modification of proteins with O-linked {beta}-N-acetylglucosamine (O-GlcNAc) is sensitive to nutrient availability and may allow cellular adaptation to different metabolic conditions. We examined how the modification of proteins with O-GlcNAc may control CCP formation and thus CME. We used perturbation of key enzymes responsible for protein O-GlcNAc modification, as well as specific mutants of the endocytic regulator AAK1 predicted to be impaired for O-GlcNAc modification. We identify that CCP initiation and the assembly of clathrin and other proteins within CCPs is controlled by O-GlcNAc protein modification. This reveals a new dimension of regulation of CME and highlights the important reciprocal regulation of cellular metabolism and endocytosis.