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. 1993 Jun 1;121(5):977–985. doi: 10.1083/jcb.121.5.977

Assembly of the 68- and 72-kD proteins of signal recognition particle with 7S RNA

PMCID: PMC2119694  PMID: 8388879

Abstract

Signal recognition particle (SRP), the cytoplasmic ribonucleoprotein particle that mediates the targeting of proteins to the ER, consists of a 7S RNA and six different proteins. The 68- (SRP68) and 72- (SRP72) kD proteins of SRP are bound to the 7S RNA of SRP as a heterodimeric complex (SRP68/72). Here we describe the primary structure of SRP72 and the assembly of SRP68, SRP72 and 7S RNA into a ribonucleoprotein particle. The amino acid sequence deduced from the cDNA of SRP72 reveals a basic protein of 671 amino acids which shares no sequence similarity with any protein in the sequence data libraries. Assembly of SRP72 into a ribonucleoprotein particle required the presence of 7S RNA and SRP68. In contrast, SRP68 alone specifically bound to 7S RNA. SRP68 contacts the 7S RNA via its NH2-terminal half while COOH-terminal portions of SRP68 and SRP72 are in contact with each other in SRP. SRP68 thus serves as a link between 7S RNA and SRP72. As a large NH2- terminal domain of SRP72 is exposed on SRP it may be a site of contact to other molecules involved in the SRP cycle between the ribosome and the ER membrane.

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Selected References

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  1. Bernstein H. D., Poritz M. A., Strub K., Hoben P. J., Brenner S., Walter P. Model for signal sequence recognition from amino-acid sequence of 54K subunit of signal recognition particle. Nature. 1989 Aug 10;340(6233):482–486. doi: 10.1038/340482a0. [DOI] [PubMed] [Google Scholar]
  2. Connolly T., Gilmore R. The signal recognition particle receptor mediates the GTP-dependent displacement of SRP from the signal sequence of the nascent polypeptide. Cell. 1989 May 19;57(4):599–610. doi: 10.1016/0092-8674(89)90129-3. [DOI] [PubMed] [Google Scholar]
  3. Elroy-Stein O., Fuerst T. R., Moss B. Cap-independent translation of mRNA conferred by encephalomyocarditis virus 5' sequence improves the performance of the vaccinia virus/bacteriophage T7 hybrid expression system. Proc Natl Acad Sci U S A. 1989 Aug;86(16):6126–6130. doi: 10.1073/pnas.86.16.6126. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Frohman M. A., Dush M. K., Martin G. R. Rapid production of full-length cDNAs from rare transcripts: amplification using a single gene-specific oligonucleotide primer. Proc Natl Acad Sci U S A. 1988 Dec;85(23):8998–9002. doi: 10.1073/pnas.85.23.8998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Fu Y. H., Kuhl D. P., Pizzuti A., Pieretti M., Sutcliffe J. S., Richards S., Verkerk A. J., Holden J. J., Fenwick R. G., Jr, Warren S. T. Variation of the CGG repeat at the fragile X site results in genetic instability: resolution of the Sherman paradox. Cell. 1991 Dec 20;67(6):1047–1058. doi: 10.1016/0092-8674(91)90283-5. [DOI] [PubMed] [Google Scholar]
  6. Gilmore R., Blobel G., Walter P. Protein translocation across the endoplasmic reticulum. I. Detection in the microsomal membrane of a receptor for the signal recognition particle. J Cell Biol. 1982 Nov;95(2 Pt 1):463–469. doi: 10.1083/jcb.95.2.463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Herz J., Flint N., Stanley K., Frank R., Dobberstein B. The 68 kDa protein of signal recognition particle contains a glycine-rich region also found in certain RNA-binding proteins. FEBS Lett. 1990 Dec 10;276(1-2):103–107. doi: 10.1016/0014-5793(90)80518-n. [DOI] [PubMed] [Google Scholar]
  8. High S., Dobberstein B. The signal sequence interacts with the methionine-rich domain of the 54-kD protein of signal recognition particle. J Cell Biol. 1991 Apr;113(2):229–233. doi: 10.1083/jcb.113.2.229. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. High S., Flint N., Dobberstein B. Requirements for the membrane insertion of signal-anchor type proteins. J Cell Biol. 1991 Apr;113(1):25–34. doi: 10.1083/jcb.113.1.25. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. High S., Görlich D., Wiedmann M., Rapoport T. A., Dobberstein B. The identification of proteins in the proximity of signal-anchor sequences during their targeting to and insertion into the membrane of the ER. J Cell Biol. 1991 Apr;113(1):35–44. doi: 10.1083/jcb.113.1.35. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Korge B. P., Gan S. Q., McBride O. W., Mischke D., Steinert P. M. Extensive size polymorphism of the human keratin 10 chain resides in the C-terminal V2 subdomain due to variable numbers and sizes of glycine loops. Proc Natl Acad Sci U S A. 1992 Feb 1;89(3):910–914. doi: 10.1073/pnas.89.3.910. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Krieg U. C., Walter P., Johnson A. E. Photocrosslinking of the signal sequence of nascent preprolactin to the 54-kilodalton polypeptide of the signal recognition particle. Proc Natl Acad Sci U S A. 1986 Nov;83(22):8604–8608. doi: 10.1073/pnas.83.22.8604. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Kurzchalia T. V., Wiedmann M., Girshovich A. S., Bochkareva E. S., Bielka H., Rapoport T. A. The signal sequence of nascent preprolactin interacts with the 54K polypeptide of the signal recognition particle. Nature. 1986 Apr 17;320(6063):634–636. doi: 10.1038/320634a0. [DOI] [PubMed] [Google Scholar]
  14. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  15. Lingelbach K., Zwieb C., Webb J. R., Marshallsay C., Hoben P. J., Walter P., Dobberstein B. Isolation and characterization of a cDNA clone encoding the 19 kDa protein of signal recognition particle (SRP): expression and binding to 7SL RNA. Nucleic Acids Res. 1988 Oct 25;16(20):9431–9442. doi: 10.1093/nar/16.20.9431. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Lütcke H., High S., Römisch K., Ashford A. J., 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. doi: 10.1002/j.1460-2075.1992.tb05199.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Meyer D. I., Krause E., Dobberstein B. Secretory protein translocation across membranes-the role of the "docking protein'. Nature. 1982 Jun 24;297(5868):647–650. doi: 10.1038/297647a0. [DOI] [PubMed] [Google Scholar]
  18. Nunnari J., Walter P. Protein targeting to and translocation across the membrane of the endoplasmic reticulum. Curr Opin Cell Biol. 1992 Aug;4(4):573–580. doi: 10.1016/0955-0674(92)90074-m. [DOI] [PubMed] [Google Scholar]
  19. Römisch K., Webb J., Herz J., Prehn S., Frank R., Vingron M., Dobberstein B. Homology of 54K protein of signal-recognition particle, docking protein and two E. coli proteins with putative GTP-binding domains. Nature. 1989 Aug 10;340(6233):478–482. doi: 10.1038/340478a0. [DOI] [PubMed] [Google Scholar]
  20. Römisch K., Webb J., Lingelbach K., Gausepohl H., Dobberstein B. The 54-kD protein of signal recognition particle contains a methionine-rich RNA binding domain. J Cell Biol. 1990 Nov;111(5 Pt 1):1793–1802. doi: 10.1083/jcb.111.5.1793. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Scoulica E., Krause E., Meese K., Dobberstein B. Disassembly and domain structure of the proteins in the signal-recognition particle. Eur J Biochem. 1987 Mar 16;163(3):519–528. doi: 10.1111/j.1432-1033.1987.tb10899.x. [DOI] [PubMed] [Google Scholar]
  22. Siegel V., Walter P. Each of the activities of signal recognition particle (SRP) is contained within a distinct domain: analysis of biochemical mutants of SRP. Cell. 1988 Jan 15;52(1):39–49. doi: 10.1016/0092-8674(88)90529-6. [DOI] [PubMed] [Google Scholar]
  23. Siegel V., Walter P. Elongation arrest is not a prerequisite for secretory protein translocation across the microsomal membrane. J Cell Biol. 1985 Jun;100(6):1913–1921. doi: 10.1083/jcb.100.6.1913. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Strub K., Walter P. Assembly of the Alu domain of the signal recognition particle (SRP): dimerization of the two protein components is required for efficient binding to SRP RNA. Mol Cell Biol. 1990 Feb;10(2):777–784. doi: 10.1128/mcb.10.2.777. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Towbin H., Staehelin T., Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4350–4354. doi: 10.1073/pnas.76.9.4350. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Walter P., Blobel G. Disassembly and reconstitution of signal recognition particle. Cell. 1983 Sep;34(2):525–533. doi: 10.1016/0092-8674(83)90385-9. [DOI] [PubMed] [Google Scholar]
  27. Walter P., Lingappa V. R. Mechanism of protein translocation across the endoplasmic reticulum membrane. Annu Rev Cell Biol. 1986;2:499–516. doi: 10.1146/annurev.cb.02.110186.002435. [DOI] [PubMed] [Google Scholar]
  28. Wolin S. L., Walter P. Signal recognition particle mediates a transient elongation arrest of preprolactin in reticulocyte lysate. J Cell Biol. 1989 Dec;109(6 Pt 1):2617–2622. doi: 10.1083/jcb.109.6.2617. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Zapp M. L. RNA nucleocytoplasmic transport. Semin Cell Biol. 1992 Aug;3(4):289–297. doi: 10.1016/1043-4682(92)90030-y. [DOI] [PubMed] [Google Scholar]
  30. Zopf D., Bernstein H. D., Johnson A. E., Walter P. The methionine-rich domain of the 54 kd protein subunit of the signal recognition particle contains an RNA binding site and can be crosslinked to a signal sequence. EMBO J. 1990 Dec;9(13):4511–4517. doi: 10.1002/j.1460-2075.1990.tb07902.x. [DOI] [PMC free article] [PubMed] [Google Scholar]

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