title: Flanking residues help determine whether a hydrophobic segment adopts a monotopic or bitopic topology in the endoplasmic reticulum membrane.
abstract: Proteins interacting with membranes via a single hydrophobic segment can be classified as either monotopic or bitopic. Here, we probe the topology of a membrane-attached enzyme, the ε isoform of human diacylglycerol kinase (DGKε), when inserted into rough microsomes and compare it with the monotopic membrane protein mouse caveolin-1. In contrast to previous findings, the N-terminal hydrophobic stretch in DGKε attains a bitopic rather than a monotopic topology in our experimental system. In addition, we find that charged flanking residues as well as proline residues embedded in the hydrophobic segment are important determinants of monotopic versus bitopic topology.
authors: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors: Morten H H
authors: MH
authors: Nørholm
authors: Yulia V
authors: YV
authors: Shulga
authors: Satoko
authors: S
authors: Aoki
authors: Richard M
authors: RM
authors: Epand
authors: Gunnar
authors: G
authors: von Heijne
references: Proc Natl Acad Sci U S A. 2001 Apr 10;98(8):4740-5
references: 11287665
references: Biochim Biophys Acta. 2009 Jun;1790(6):416-24
references: 19364481
references: Proteomics. 2004 Jun;4(6):1633-49
references: 15174133
references: Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9407-11
references: 7568142
references: Proc Natl Acad Sci U S A. 2008 Mar 18;105(11):4127-32
references: 18326626
references: Biochemistry. 2007 May 22;46(20):6109-17
references: 17455907
references: J Mol Biol. 2011 Mar 18;407(1):171-9
references: 21262233
references: Nature. 2005 Jan 27;433(7024):377-81
references: 15674282
references: Science. 2010 Jun 25;328(5986):1698-700
references: 20508091
references: Biochim Biophys Acta. 2007 Oct;1768(10):2549-58
references: 17669357
references: J Mol Biol. 2008 Nov 21;383(4):797-809
references: 18801368
references: J Mol Biol. 2010 Feb 12;396(1):221-9
references: 19931281
references: J Biol Chem. 1998 Mar 6;273(10):5419-22
references: 9488658
references: Proc Natl Acad Sci U S A. 2009 Feb 10;106(6):1760-5
references: 19181854
references: Proc Natl Acad Sci U S A. 1980 Mar;77(3):1496-500
references: 6929499
references: Proc Natl Acad Sci U S A. 1996 Jun 25;93(13):6676-81
references: 8692877
references: Proc Natl Acad Sci U S A. 2008 Oct 14;105(41):15702-7
references: 18840693
references: Cell. 2011 Feb 4;144(3):402-13
references: 21295700
references: J Mol Biol. 2005 Jan 14;345(2):339-50
references: 15571726
references: Nucleic Acids Res. 2006;34(18):e122
references: 17000637
references: Genome Biol. 2004;5(3):214
references: 15003112
references: Protein Sci. 2005 Jul;14(7):1723-8
references: 15987901
references: J Biol Chem. 1999 Aug 6;274(32):22660-7
references: 10428847
references: J Biol Chem. 2010 Oct 22;285(43):33371-33380
references: 20729193
references: J Mol Biol. 1999 Nov 5;293(4):807-14
references: 10543969
references: Nature. 2007 Dec 13;450(7172):1026-30
references: 18075582
references: BMC Biotechnol. 2010 Mar 16;10:21
references: 20233396