title: To flip or not to flip: lipid-protein charge interactions are a determinant of final membrane protein topology.
abstract: The molecular details of how lipids influence final topological organization of membrane proteins are not well understood. Here, we present evidence that final topology is influenced by lipid-protein interactions most likely outside of the translocon. The N-terminal half of Escherichia coli lactose permease (LacY) is inverted with respect to the C-terminal half and the membrane bilayer when assembled in mutants lacking phosphatidylethanolamine and containing only negatively charged phospholipids. We demonstrate that inversion is dependent on interactions between the net charge of the cytoplasmic surface of the N-terminal bundle and the negative charge density of the membrane bilayer surface. A transmembrane domain, acting as a molecular hinge between the two halves of the protein, must also exit from the membrane for inversion to occur. Phosphatidylethanolamine dampens the translocation potential of negative residues in favor of the cytoplasmic retention potential of positive residues, thus explaining the dominance of positive over negative amino acids as co- or post-translational topological determinants.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas-Houston Medical School and Graduate School of Biomedical Sciences, Houston, TX 77225, USA.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Bogdanov
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
authors.forename: Phil
authors.initials: P
authors.lastname: Heacock
authors.forename: William
authors.initials: W
authors.lastname: Dowhan
mesh_terms: D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D057927:Hydrophobic and Hydrophilic Interactions; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D010714:Phosphatidylethanolamines / Q000378:metabolism; D017434:Protein Structure, Tertiary; D027981:Symporters / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology
chemical_list: D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D008563:Membrane Lipids; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D010714:Phosphatidylethanolamines; D027981:Symporters; C483858:phosphatidylethanolamine
references.citation: Methods. 2005 Jun;36(2):148-71
references.pmid: 15894490
references.citation: FASEB J. 1998 Oct;12(13):1281-99
references.pmid: 9761772
references.citation: EMBO J. 2003 Jul 15;22(14):3645-53
references.pmid: 12853479
references.citation: Gene. 1989 Apr 15;77(1):51-9
references.pmid: 2744487
references.citation: J Biol Chem. 1995 Jan 13;270(2):732-9
references.pmid: 7822303
references.citation: J Biol Chem. 2003 Apr 25;278(17):14820-6
references.pmid: 12590141
references.citation: J Biol Chem. 1991 Mar 15;266(8):5323-32
references.pmid: 2002065
references.citation: J Biol Chem. 1998 Apr 17;273(16):9927-34
references.pmid: 9545336
references.citation: Nat Rev Mol Cell Biol. 2006 Dec;7(12):909-18
references.pmid: 17139331
references.citation: Protein Sci. 2006 Jun;15(6):1318-33
references.pmid: 16731967
references.citation: Mol Biol Cell. 2004 Mar;15(3):1470-8
references.pmid: 14668483
references.citation: J Biol Chem. 2003 Dec 12;278(50):50128-35
references.pmid: 14525982
references.citation: J Biol Chem. 2005 Jul 15;280(28):26032-8
references.pmid: 15890647
references.citation: EMBO J. 1997 Jul 16;16(14):4261-6
references.pmid: 9250669
references.citation: Nature. 1989 Oct 5;341(6241):456-8
references.pmid: 2677744
references.citation: Mol Microbiol. 2003 Jun;48(5):1145-56
references.pmid: 12787345
references.citation: Nature. 2005 Dec 1;438(7068):581-9
references.pmid: 16319877
references.citation: Cell. 1990 Sep 21;62(6):1135-41
references.pmid: 2119256
references.citation: Science. 2003 Aug 1;301(5633):610-5
references.pmid: 12893935
references.citation: EMBO J. 1995 Mar 1;14(5):866-75
references.pmid: 7889937
references.citation: J Biol Chem. 1999 Nov 19;274(47):33757-63
references.pmid: 10559268
references.citation: Chem Rev. 2006 May;106(5):1931-77
references.pmid: 16683762
references.citation: FEMS Microbiol Lett. 2006 Sep;262(2):178-84
references.pmid: 16923073
references.citation: Science. 2005 Mar 4;307(5714):1427
references.pmid: 15681341
references.citation: EMBO J. 2002 Nov 1;21(21):5673-81
references.pmid: 12411485
references.citation: J Cell Biol. 2007 Dec 31;179(7):1441-52
references.pmid: 18166653
references.citation: Biochem J. 2008 May 1;411(3):495-506
references.pmid: 18248332
references.citation: EMBO J. 2002 May 1;21(9):2107-16
references.pmid: 11980707
references.citation: EMBO J. 1994 May 15;13(10):2267-72
references.pmid: 8194517
references.citation: EMBO J. 1994 Oct 3;13(19):4662-9
references.pmid: 7925307
references.citation: Nature. 2004 Jan 1;427(6969):36-44
references.pmid: 14661030
references.citation: Bioinformatics. 2006 Jul 15;22(14):e290-7
references.pmid: 16873484
references.citation: J Biol Chem. 2006 Jul 14;281(28):19172-8
references.pmid: 16698795
references.citation: J Biol Chem. 2008 Apr 4;283(14):9369-76
references.pmid: 18234676
references.citation: J Biol Chem. 1992 Sep 5;267(25):17809-19
references.pmid: 1517220
references.citation: Biochemistry. 1999 Jun 29;38(26):8590-7
references.pmid: 10387107
references.citation: Cell. 1997 May 16;89(4):535-44
references.pmid: 9160745
references.citation: Cell Mol Life Sci. 2007 Jun;64(12):1571-82
references.pmid: 17530171
references.citation: Plasmid. 1992 Jul;28(1):14-24
references.pmid: 1387714
references.citation: Biochemistry. 2006 Jul 4;45(26):8088-95
references.pmid: 16800633
references.citation: Biochim Biophys Acta. 2004 Nov 3;1666(1-2):19-39
references.pmid: 15519306
references.citation: Mol Membr Biol. 2004 Jul-Aug;21(4):227-36
references.pmid: 15371012
references.citation: J Biol Chem. 1995 Jan 27;270(4):1742-6
references.pmid: 7829509
references.citation: Mol Microbiol. 1991 Sep;5(9):2243-53
references.pmid: 1766388
references.citation: Biochemistry. 2000 Sep 5;39(35):10641-8
references.pmid: 10978147
references.citation: J Biol Chem. 2002 Apr 12;277(15):12718-23
references.pmid: 11821429
references.citation: J Bacteriol. 2002 Nov;184(21):5842-7
references.pmid: 12374816
references.citation: Proc Natl Acad Sci U S A. 1989 Aug;86(15):5786-90
references.pmid: 2762295
references.citation: Nucleic Acids Res. 1997 Mar 15;25(6):1203-10
references.pmid: 9092630
references.citation: Nat Struct Mol Biol. 2005 Oct;12(10):870-8
references.pmid: 16186821