Biomolecular condensation orchestrates clathrin-mediated endocytosis in plants

Summary Clathrin-mediated endocytosis (CME) is an essential cellular internalisation pathway involving the dynamic assembly of clathrin and accessory proteins to form membrane-bound vesicles. In plants, the evolutionarily ancient TSET/TPLATE complex (TPC) plays an essential, but not well-defined role in CME. Here, we show that two highly disordered TPC subunits, AtEH1 and AtEH2 function as scaffolds to drive biomolecular condensation of the complex. These condensates specifically nucleate on the plasma membrane through interactions with anionic phospholipids, and facilitate the dynamic recruitment and assembly of clathrin, early-, and late-stage endocytic accessory proteins. Importantly, clathrin forms ordered assemblies within the condensate environment. Biomolecular condensation therefore acts to promote dynamic protein assemblies throughout clathrin-mediated endocytosis. Furthermore, the disordered region sequence properties of AtEH1 regulate the material properties of the endocytic condensates in vivo and alteration of these material properties influences endocytosis dynamics, and consequently plant adaptive growth. Highlights AtEH subunits are endocytic scaffolds which drive condensation of the TPC AtEH1 condensates nucleate on the plasma membrane via lipid interactions Condensation of AtEH1/TPC facilitates clathrin re-arrangement and assembly AtEH1 IDR1 composition controls condensate properties to regulate endocytosis