Clathrin-associated carriers enable recycling through a kiss-and-run mechanism

Abstract Endocytosis and recycling control the uptake and retrieval of various materials, including membrane proteins and lipids, in all eukaryotic cells. These processes are crucial for cell growth, organization, function, and environmental communication. However, the mechanisms underlying efficient, fast endocytic recycling remain poorly understood. Here, by utilizing a biosensor and imaged-based screening, we uncover a novel recycling mechanism that couples endocytosis and fast recycling, which we name the clathrin-associated fast endosomal recycling pathway (CARP). Clathrin-associated tubulovesicular carriers containing clathrin, AP1, Arf1, Rab1, and Rab11, while lacking the multimeric retrieval complexes, are generated at subdomains of early endosomes, and then transported along actin to cell surfaces. Unexpectedly, the clathrin-associated recycling carriers undergo partial fusion with the plasma membrane. Subsequently, they are released from the membrane by dynamin and reenter cells. Multiple receptors utilize and modulate CARP for fast recycling following endocytosis. Thus, CARP represents a novel endocytic recycling mechanism with kiss-and-run membrane fusion.