TANGO1 membrane helices create a lipid diffusion barrier at curved membranes
Abstract
We have previously shown TANGO1 organises membranes at the interface of the endoplasmic reticulum (ER) and ERGIC/Golgi (Raote et al., 2018). TANGO1 corrals retrograde membranes at ER exit sites to create an export conduit. Here the retrograde membrane is, in itself, an anterograde carrier. This mode of forward transport necessitates a mechanism to prevent membrane mixing between ER and the retrograde membrane. TANGO1 has an unusual membrane helix organisation, composed of one membrane-spanning helix (TM) and another that penetrates the inner leaflet (IM). We have reconstituted these membrane helices in model membranes and shown that TM and IM together reduce the flow of lipids at a region of defined shape. We have also shown that the helices align TANGO1 around an ER exit site. We suggest this is a mechanism to prevent membrane mixing during TANGO1-mediated transfer of bulky secretory cargos from the ER to the ERGIC/Golgi via a tunnel.
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Funding
Ministerio de Economía y Competitividad (SEV-2012-0208)
- Ishier Raote
- Vivek Malhotra
Generalitat de Catalunya (CERCA)
- Felix Campelo
Ministerio de Economía y Competitividad (BFU2013-44188-P)
- Ishier Raote
- Vivek Malhotra
Ministerio de Economía y Competitividad (CSD2009-00016)
- Ishier Raote
- Vivek Malhotra
Ministerio de Economía y Competitividad (IJCI-2017-34751)
- Ishier Raote
National Institutes of Health (R35 GM118084)
- James E Rothman
Ministerio de Economía y Competitividad (SEV-2015-0522)
- Felix Campelo
Ministerio de Economía y Competitividad (RYC-2017-22227)
- Felix Campelo
Fundacio Privada Cellex
- Felix Campelo
Fundacio Privada Mir-Puig
- Felix Campelo
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Raote et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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