title: Structural and functional profiling of the lateral gate of the Sec61 translocon.
abstract: The evolutionarily conserved Sec61 translocon mediates the translocation and membrane insertion of proteins. For the integration of proteins into the membrane, the Sec61 translocon opens laterally to the lipid bilayer. Previous studies suggest that the lateral opening of the channel is mediated by the helices TM2b and TM7 of a pore-forming subunit of the Sec61 translocon. To map key residues in TM2b and TM7 in yeast Sec61 that modulate lateral gating activity, we performed alanine scanning and in vivo site-directed photocross-linking experiments. Alanine scanning identified two groups of critical residues in the lateral gate, one group that leads to defects in the translocation and membrane insertion of proteins and the other group that causes faster translocation and facilitates membrane insertion. Photocross-linking data show that the former group of residues is located at the interface of the lateral gate. Furthermore, different degrees of defects for the membrane insertion of single- and double-spanning membrane proteins were observed depending on whether the mutations were located in TM2b or TM7. These results demonstrate subtle differences in the molecular mechanism of the signal sequence binding/opening of the lateral gate and membrane insertion of a succeeding transmembrane segment in a polytopic membrane protein.
authors.affiliation: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Johannes H
authors.initials: JH
authors.lastname: Reithinger
authors.affiliation: From the School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea and.
authors.forename: Chewon
authors.initials: C
authors.lastname: Yim
authors.affiliation: From the School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea and.
authors.forename: Sungmin
authors.initials: S
authors.lastname: Kim
authors.affiliation: From the School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea and.
authors.forename: Hunsang
authors.initials: H
authors.lastname: Lee
authors.affiliation: From the School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea and joy@snu.ac.kr.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D021381:Protein Transport / Q000502:physiology; D000069816:SEC Translocation Channels; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D008051:Lipid Bilayers; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; C499383:SEC61 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
keywords: Endoplasmic Reticulum (ER); Membrane; Membrane Protein; Protein Translocation; Yeast
references.citation: Cell. 1998 Sep 18;94(6):795-807
references.pmid: 9753326
references.citation: J Bacteriol. 2005 Sep;187(18):6454-65
references.pmid: 16159779
references.citation: Mol Biol Cell. 2010 May 15;21(10):1662-70
references.pmid: 20357000
references.citation: Biochim Biophys Acta. 2011 Mar;1808(3):912-24
references.pmid: 20599535
references.citation: Mol Biol Cell. 2011 Sep;22(17):2983-93
references.pmid: 21737680
references.citation: Cell Rep. 2012 Oct 25;2(4):927-37
references.pmid: 23084746
references.citation: Anal Biochem. 1989 Jul;180(1):147-51
references.pmid: 2530914
references.citation: Biotechniques. 2007 Feb;42(2):158, 160, 162
references.pmid: 17373478
references.citation: Cell. 2000 Jul 21;102(2):233-44
references.pmid: 10943843
references.citation: Nature. 1991 Feb 28;349(6312):806-8
references.pmid: 2000150
references.citation: Mol Cell. 2012 Nov 9;48(3):398-408
references.pmid: 23022384
references.citation: Structure. 2009 Nov 11;17(11):1453-64
references.pmid: 19913480
references.citation: Cell. 1995 May 19;81(4):561-70
references.pmid: 7758110
references.citation: Proc Natl Acad Sci U S A. 2010 Oct 5;107(40):17182-7
references.pmid: 20855604
references.citation: Nature. 2011 May 12;473(7346):239-42
references.pmid: 21562565
references.citation: Mol Biol Cell. 2004 Mar;15(3):1470-8
references.pmid: 14668483
references.citation: Proc Natl Acad Sci U S A. 2013 Nov 19;110(47):18856-61
references.pmid: 24191046
references.citation: J Biol Chem. 2007 Jan 12;282(2):1281-7
references.pmid: 17092931
references.citation: J Cell Biol. 2012 Dec 10;199(6):907-18
references.pmid: 23229898
references.citation: J Mol Biol. 2009 Mar 13;386(5):1222-8
references.pmid: 19452628
references.citation: Mol Biol Cell. 2006 Sep;17(9):4063-8
references.pmid: 16822836
references.citation: Mol Cell. 2007 May 25;26(4):511-21
references.pmid: 17531810
references.citation: Nucleic Acids Res. 1989 Aug 25;17(16):6545-51
references.pmid: 2674899
references.citation: Nature. 2007 Nov 29;450(7170):663-9
references.pmid: 18046402
references.citation: Proc Natl Acad Sci U S A. 2008 Oct 14;105(41):15702-7
references.pmid: 18840693
references.citation: EMBO J. 1996 Apr 1;15(7):1482-94
references.pmid: 8612571
references.citation: Biochem J. 2008 May 1;411(3):495-506
references.pmid: 18248332
references.citation: J Am Chem Soc. 2011 Oct 5;133(39):15487-95
references.pmid: 21861483
references.citation: Nature. 2014 Feb 6;506(7486):107-10
references.pmid: 24499919
references.citation: Nature. 2004 Jan 1;427(6969):36-44
references.pmid: 14661030
references.citation: Nature. 2008 Oct 16;455(7215):988-91
references.pmid: 18923527
references.citation: Structure. 2010 Jul 14;18(7):847-57
references.pmid: 20637421
references.citation: Mol Biol Cell. 2009 Jan;20(2):685-98
references.pmid: 19019984
references.citation: Science. 2003 Aug 15;301(5635):964-7
references.pmid: 12920298
references.citation: J Biol Chem. 2007 Nov 9;282(45):33201-9
references.pmid: 17893139
references.citation: Annu Rev Cell Dev Biol. 2005;21:529-50
references.pmid: 16212506
references.citation: J Mol Biol. 2007 Aug 3;371(1):112-22
references.pmid: 17560600
references.citation: Nature. 2007 Dec 13;450(7172):1026-30
references.pmid: 18075582
references.citation: J Biol Chem. 2013 Jun 21;288(25):18058-67
references.pmid: 23632075
references.citation: Nature. 2005 Jan 27;433(7024):377-81
references.pmid: 15674282
references.citation: Nature. 2008 Oct 16;455(7215):936-43
references.pmid: 18923516
references.citation: Dev Cell. 2001 Sep;1(3):401-9
references.pmid: 11702951
references.citation: Cell. 1981 Jan;23(1):79-88
references.pmid: 7011570
references.citation: EMBO J. 1997 Aug 1;16(15):4540-8
references.pmid: 9303298
references.citation: J Biol Chem. 2009 Jun 5;284(23):15805-14
references.pmid: 19366685
references.citation: EMBO J. 2003 Jul 15;22(14):3654-63
references.pmid: 12853480
references.citation: Proc Natl Acad Sci U S A. 2013 Sep 3;110(36):14640-5
references.pmid: 23959879
references.citation: Nat Struct Mol Biol. 2005 Oct;12(10):870-8
references.pmid: 16186821