TY - JOUR
T1 - Mechanism of membrane-curvature generation by ER-tubule shaping proteins
AU - Wang, Ning
AU - Clark, Lindsay D.
AU - Gao, Yuan
AU - Kozlov, Michael M.
AU - Shemesh, Tom
AU - Rapoport, Tom A.
N1 - Funding Information: We thank Snezhana Oliferenko, Sophie Martin, I-Ju Lee, Jian-Qiu Wu, and Susan Wente for sharing yeast strains and reagents; the Nikon Imaging Center, the Center for Macromolecular Interactions, and the Electron Microscopy Facility at Harvard Medical School for technical assistance; and Bradley French, and Yoko Shibata for critical reading of the manuscript. L.D.C was supported by a fellowship from the American Heart Association (20POST35140000), Y.G. by a fellowship from the Damon Runyon Cancer Research Foundation (DRG-[2354-19]), M.M.K by the Israel Science Foundation (3292/ 19) and the Deutsche Forschungsgemeinschaft (DFG) (SFB 958), and T.S. by the Israel Science Foundation (2751/20). T.A.R. is a Howard Hughes Medical Institute investigator. Publisher Copyright: © 2021, The Author(s).
PY - 2021/1/25
Y1 - 2021/1/25
N2 - The endoplasmic reticulum (ER) network consists of tubules with high membrane curvature in cross-section, generated by the reticulons and REEPs. These proteins have two pairs of trans-membrane (TM) segments, followed by an amphipathic helix (APH), but how they induce curvature is poorly understood. Here, we show that REEPs form homodimers by interaction within the membrane. When overexpressed or reconstituted at high concentrations with phospholipids, REEPs cause extreme curvature through their TMs, generating lipoprotein particles instead of vesicles. The APH facilitates curvature generation, as its mutation prevents ER network formation of reconstituted proteoliposomes, and synthetic L- or D-amino acid peptides abolish ER network formation in Xenopus egg extracts. In Schizosaccharomyces japonicus, the APH is required for reticulon’s exclusive ER-tubule localization and restricted mobility. Thus, the TMs and APH cooperate to generate high membrane curvature. We propose that the formation of splayed REEP/reticulon dimers is responsible for ER tubule formation.
AB - The endoplasmic reticulum (ER) network consists of tubules with high membrane curvature in cross-section, generated by the reticulons and REEPs. These proteins have two pairs of trans-membrane (TM) segments, followed by an amphipathic helix (APH), but how they induce curvature is poorly understood. Here, we show that REEPs form homodimers by interaction within the membrane. When overexpressed or reconstituted at high concentrations with phospholipids, REEPs cause extreme curvature through their TMs, generating lipoprotein particles instead of vesicles. The APH facilitates curvature generation, as its mutation prevents ER network formation of reconstituted proteoliposomes, and synthetic L- or D-amino acid peptides abolish ER network formation in Xenopus egg extracts. In Schizosaccharomyces japonicus, the APH is required for reticulon’s exclusive ER-tubule localization and restricted mobility. Thus, the TMs and APH cooperate to generate high membrane curvature. We propose that the formation of splayed REEP/reticulon dimers is responsible for ER tubule formation.
KW - Animals
KW - Cell Membrane/metabolism
KW - Endoplasmic Reticulum/metabolism
KW - Fungal Proteins/chemistry
KW - Lipoproteins/chemistry
KW - Membrane Proteins/chemistry
KW - Microscopy, Electron
KW - Mutation
KW - Protein Multimerization
KW - Schizosaccharomyces
KW - Xenopus Proteins/chemistry
UR - https://www.scopus.com/pages/publications/85099756728
U2 - 10.1038/s41467-020-20625-y
DO - 10.1038/s41467-020-20625-y
M3 - Article
C2 - 33495454
SN - 2041-1723
VL - 12
SP - 568
JO - Nature communications
JF - Nature communications
IS - 1
M1 - 568
ER -