The ER morphology-regulating lunapark protein induces the formation of stacked bilayer discs

  • Lunapark (Lnp) is a conserved membrane protein that localizes to and stabilizes three-way junctions of the tubular ER network. In higher eukaryotes, phosphorylation of Lnp may contribute to the conversion of the ER from tubules to sheets during mitosis. Here, we report on the reconstitution of purified Lnp with phospholipids. Surprisingly, Lnp induces the formation of stacked membrane discs. Each disc is a bicelle, with Lnp sitting in the bilayer facing both directions. The interaction between bicelles is mediated by the cytosolic domains of Lnp, resulting in a constant distance between the discs. A phosphomimetic Lnp mutant shows reduced bicelle stacking. Based on these results, we propose that Lnp tethers ER membranes in vivo in a cell cycle–dependent manner. Lnp appears to be the first membrane protein that induces the formation of stacked bicelles.

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Author:Songyu Wang, Robert Powers, Vicki A. M. Gold, Tom A. Rapoport
Pubmed Id:
Parent Title (English):Life science alliance
Publisher:EMBO Press
Place of publication:Heidelberg
Document Type:Article
Year of Completion:2018
Date of first Publication:2018/01/19
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2018/12/13
Issue:1, e201700014
Page Number:11
First Page:1
Last Page:11
© 2018 Wang et al
This article is available under a Creative Commons License (Attribution 4.0 International, as described at
Institutes:Biowissenschaften / Biowissenschaften
Angeschlossene und kooperierende Institutionen / MPI für Biophysik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Licence (German):License LogoCreative Commons - Namensnennung 4.0