Dynamin-2 is a fission factor for SNX1-coated endosomal tubules

Abstract

Sorting nexins of the SNX-BAR family shape endosomal membranes into tubular carriers that route cargo away from the degradative pathway, but we poorly understand the machinery that cuts these tubules to release transport carriers. Here we show that Dynamin-2 (Dyn2) is a fission factor for SNX1-coated tubules. In HeLa cells, Dyn2 localises to SNX1 tubules, and its knockout lengthens them and produces interconnected networks. Dyn2 binds SNX1 directly, and this interaction requires both the proline-rich domain of Dyn2 and the N-terminus of SNX1. On supported lipid bilayers, SNX1 alone tubulates membranes, and adding Dyn2 and GTP converts the emergent tubules into vesicles, indicating that no additional factors are needed for this activity. In cells, loss of Dyn2 redirects the retromer cargo GLUT1 to a LAMP1-positive compartment and reduces glucose uptake. These findings identify Dyn2 as the enzyme that releases SNX1 carriers and link this scission step to cargo recycling.