Raote, IshierChabanon, MorganWalani, NikhilArroyo, MarinoGarcia-Parajo, Maria F.Malhotra, VivekCampelo, Felix2020-12-162020-12-162020Raote I, Chabanon M,Walani N, Arroyo M, Garcia-Parajo MF, Malhotra M et al. A physical mechanism of TANGO1-mediated bulky cargo export. Elife. 2020 Nov 10;9:e59426. DOI: 10.7554/eLife.594262050-084Xhttp://hdl.handle.net/10230/46059The endoplasmic reticulum (ER)-resident protein TANGO1 assembles into a ring around ER exit sites (ERES), and links procollagens in the ER lumen to COPII machinery, tethers, and ER-Golgi intermediate compartment (ERGIC) in the cytoplasm (Raote et al., 2018). Here, we present a theoretical approach to investigate the physical mechanisms of TANGO1 ring assembly and how COPII polymerization, membrane tension, and force facilitate the formation of a transport intermediate for procollagen export. Our results indicate that a TANGO1 ring, by acting as a linactant, stabilizes the open neck of a nascent COPII bud. Elongation of such a bud into a transport intermediate commensurate with bulky procollagens is then facilitated by two complementary mechanisms: (i) by relieving membrane tension, possibly by TANGO1-mediated fusion of retrograde ERGIC membranes and (ii) by force application. Altogether, our theoretical approach identifies key biophysical events in TANGO1-driven procollagen export.application/pdfeng© 2020, Raote et al. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are creditedCitologiaProteïnesinfo:eu-repo/semantics/articlehttp://dx.doi.org/10.7554/eLife.59426info:eu-repo/semantics/openAccess