ARF-1 Coordinates Cargo Sorting at FERARI Endosomal Recycling Hubs

Abstract

Endosomal pathways are central to cellular organization, compartmentalization, and intercellular communication. Independent of the endocytic entry route, sorting endosomes function as critical junctions at which membrane proteins are sorted for recycling or degradation. The multicomponent tether FERARI orchestrates recycling by coordinating Rab GTPase activity with vesicle fusion and fission through a kiss-and-run mechanism. Here, we identify the small GTPase ARF-1 as an essential regulator of cargo loading at FERARI-dependent endosomal kiss-and-run (KAR) sites. Cycling of ARF-1 between its active and inactive states is required for efficient cargo capture into recycling vesicles. Our findings support a model in which cycling ARF-1 activity governs the temporal association of cargo with adaptor proteins and complexes, thereby controlling selective uptake into vesicles destined for the plasma membrane. These results uncover a previously unappreciated layer of regulation of endosomal recycling and highlight the interplay between ARF and Rab family GTPases in this process.