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J Cell Biol. 1994 September 1; 126(5): 1127–1132.
PMCID: PMC2120157

The COOH-terminal ends of internal signal and signal-anchor sequences are positioned differently in the ER translocase


Signal peptides (SPs) target proteins to the secretory pathway and are cleaved from the nascent chain once the translocase in the ER has been engaged. Signal-anchor (SA) sequences also interact transiently with the ER translocase, but are not cleaved and move laterally out of the translocase to become permanent membrane anchors. One obvious difference between SP and SA sequences is the considerably longer hydrophobic regions (h regions) of the latter. To study the interaction between SP/SA sequences and the ER translocase, we have constructed signal sequences with poly-Leu h regions ranging in length from 8 to 29 residues and have characterized their locations within the translocase using both a new assay that measures the minimum number of amino acids needed to span the distance between the COOH-terminal end of the h region and the active site of the oligosaccharyl transferase enzyme and an assay where the efficiency of signal peptidase catalyzed cleavage is measured. Our results suggest that SP and SA sequences are positioned differently in the ER translocase.

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Selected References

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  • Bairoch A, Boeckmann B. The SWISS-PROT protein sequence data bank. Nucleic Acids Res. 1991 Apr 25;19 (Suppl):2247–2249. [PMC free article] [PubMed]
  • Chou MM, Kendall DA. Polymeric sequences reveal a functional interrelationship between hydrophobicity and length of signal peptides. J Biol Chem. 1990 Feb 15;265(5):2873–2880. [PubMed]
  • Crowley KS, Reinhart GD, Johnson AE. The signal sequence moves through a ribosomal tunnel into a noncytoplasmic aqueous environment at the ER membrane early in translocation. Cell. 1993 Jun 18;73(6):1101–1115. [PubMed]
  • Dalbey RE, Von Heijne G. Signal peptidases in prokaryotes and eukaryotes--a new protease family. Trends Biochem Sci. 1992 Nov;17(11):474–478. [PubMed]
  • Feldheim D, Yoshimura K, Admon A, Schekman R. Structural and functional characterization of Sec66p, a new subunit of the polypeptide translocation apparatus in the yeast endoplasmic reticulum. Mol Biol Cell. 1993 Sep;4(9):931–939. [PMC free article] [PubMed]
  • Gavel Y, von Heijne G. Sequence differences between glycosylated and non-glycosylated Asn-X-Thr/Ser acceptor sites: implications for protein engineering. Protein Eng. 1990 Apr;3(5):433–442. [PubMed]
  • Gilmore R. Protein translocation across the endoplasmic reticulum: a tunnel with toll booths at entry and exit. Cell. 1993 Nov 19;75(4):589–592. [PubMed]
  • Görlich D, Prehn S, Hartmann E, Kalies KU, Rapoport TA. A mammalian homolog of SEC61p and SECYp is associated with ribosomes and nascent polypeptides during translocation. Cell. 1992 Oct 30;71(3):489–503. [PubMed]
  • Görlich D, Rapoport TA. Protein translocation into proteoliposomes reconstituted from purified components of the endoplasmic reticulum membrane. Cell. 1993 Nov 19;75(4):615–630. [PubMed]
  • Haeuptle MT, Frank R, Dobberstein B. Translation arrest by oligodeoxynucleotides complementary to mRNA coding sequences yields polypeptides of predetermined length. Nucleic Acids Res. 1986 Feb 11;14(3):1427–1448. [PMC free article] [PubMed]
  • Hartmann E, Sommer T, Prehn S, Görlich D, Jentsch S, Rapoport TA. Evolutionary conservation of components of the protein translocation complex. Nature. 1994 Feb 17;367(6464):654–657. [PubMed]
  • Hegner M, von Kieckebusch-Gück A, Falchetto R, James P, Semenza G, Mantei N. Single amino acid substitutions can convert the uncleaved signal-anchor of sucrase-isomaltase to a cleaved signal sequence. J Biol Chem. 1992 Aug 25;267(24):16928–16933. [PubMed]
  • High S, Andersen SS, Görlich D, Hartmann E, Prehn S, Rapoport TA, Dobberstein B. Sec61p is adjacent to nascent type I and type II signal-anchor proteins during their membrane insertion. J Cell Biol. 1993 May;121(4):743–750. [PMC free article] [PubMed]
  • High S, Martoglio B, Görlich D, Andersen SS, Ashford AJ, Giner A, Hartmann E, Prehn S, Rapoport TA, Dobberstein B, et al. Site-specific photocross-linking reveals that Sec61p and TRAM contact different regions of a membrane-inserted signal sequence. J Biol Chem. 1993 Dec 15;268(35):26745–26751. [PubMed]
  • Johansson M, Nilsson I, von Heijne G. Positively charged amino acids placed next to a signal sequence block protein translocation more efficiently in Escherichia coli than in mammalian microsomes. Mol Gen Genet. 1993 May;239(1-2):251–256. [PubMed]
  • Kozak M. Context effects and inefficient initiation at non-AUG codons in eucaryotic cell-free translation systems. Mol Cell Biol. 1989 Nov;9(11):5073–5080. [PMC free article] [PubMed]
  • Kunkel TA. Rapid and efficient site-specific mutagenesis without phenotypic selection. Proc Natl Acad Sci U S A. 1985 Jan;82(2):488–492. [PubMed]
  • Kurzchalia TV, Wiedmann M, Girshovich AS, Bochkareva ES, Bielka H, Rapoport TA. The signal sequence of nascent preprolactin interacts with the 54K polypeptide of the signal recognition particle. Nature. 1986 Apr 17;320(6063):634–636. [PubMed]
  • Liljeström P, Garoff H. Internally located cleavable signal sequences direct the formation of Semliki Forest virus membrane proteins from a polyprotein precursor. J Virol. 1991 Jan;65(1):147–154. [PMC free article] [PubMed]
  • Lipp J, Dobberstein B. The membrane-spanning segment of invariant chain (I gamma) contains a potentially cleavable signal sequence. Cell. 1986 Sep 26;46(7):1103–1112. [PubMed]
  • Lipp J, Flint N, Haeuptle MT, Dobberstein B. Structural requirements for membrane assembly of proteins spanning the membrane several times. J Cell Biol. 1989 Nov;109(5):2013–2022. [PMC free article] [PubMed]
  • Lütcke H, High S, Römisch K, Ashford AJ, Dobberstein B. The methionine-rich domain of the 54 kDa subunit of signal recognition particle is sufficient for the interaction with signal sequences. EMBO J. 1992 Apr;11(4):1543–1551. [PubMed]
  • Miao GH, Hong Z, Verma DP. Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane. J Cell Biol. 1992 Jul;118(2):481–490. [PMC free article] [PubMed]
  • Nilsson I, von Heijne G. A de novo designed signal peptide cleavage cassette functions in vivo. J Biol Chem. 1991 Feb 25;266(6):3408–3410. [PubMed]
  • Nilsson IM, von Heijne G. Determination of the distance between the oligosaccharyltransferase active site and the endoplasmic reticulum membrane. J Biol Chem. 1993 Mar 15;268(8):5798–5801. [PubMed]
  • Roy P, Chatellard C, Lemay G, Crine P, Boileau G. Transformation of the signal peptide/membrane anchor domain of a type II transmembrane protein into a cleavable signal peptide. J Biol Chem. 1993 Feb 5;268(4):2699–2704. [PubMed]
  • Sakaguchi M, Tomiyoshi R, Kuroiwa T, Mihara K, Omura T. Functions of signal and signal-anchor sequences are determined by the balance between the hydrophobic segment and the N-terminal charge. Proc Natl Acad Sci U S A. 1992 Jan 1;89(1):16–19. [PubMed]
  • Schmid SR, Spiess M. Deletion of the amino-terminal domain of asialoglycoprotein receptor H1 allows cleavage of the internal signal sequence. J Biol Chem. 1988 Nov 15;263(32):16886–16891. [PubMed]
  • von Heijne G. Analysis of the distribution of charged residues in the N-terminal region of signal sequences: implications for protein export in prokaryotic and eukaryotic cells. EMBO J. 1984 Oct;3(10):2315–2318. [PubMed]
  • von Heijne G. Signal sequences. The limits of variation. J Mol Biol. 1985 Jul 5;184(1):99–105. [PubMed]
  • von Heijne G. Towards a comparative anatomy of N-terminal topogenic protein sequences. J Mol Biol. 1986 May 5;189(1):239–242. [PubMed]
  • von Heijne G. Transcending the impenetrable: how proteins come to terms with membranes. Biochim Biophys Acta. 1988 Jun 9;947(2):307–333. [PubMed]
  • von Heijne G. Membrane proteins: from sequence to structure. Annu Rev Biophys Biomol Struct. 1994;23:167–192. [PubMed]
  • Walter P, Blobel G. Preparation of microsomal membranes for cotranslational protein translocation. Methods Enzymol. 1983;96:84–93. [PubMed]
  • Walter P, Blobel G. Signal recognition particle: a ribonucleoprotein required for cotranslational translocation of proteins, isolation and properties. Methods Enzymol. 1983;96:682–691. [PubMed]
  • Wessels HP, Spiess M. Insertion of a multispanning membrane protein occurs sequentially and requires only one signal sequence. Cell. 1988 Oct 7;55(1):61–70. [PubMed]

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