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

Lütcke, Henrich; Prehn, Siegfried; Ashford, Anthony J.; Remus, Michael; Frank, Rainer; Dobberstein, Bernhard

doi:10.1083/jcb.121.5.977

Cited by 50 publications

(48 citation statements)

References 32 publications

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“…The SRP68͞SRP72 complex from the SRP also binds SRP RNA independently from the other SRP proteins, but the interaction is stabilized by SRP19 and͞or SRP54 binding (27). When in vitro expressed proteins are studied, SRP68 binds SRP RNA before SRP72, but its binding is stabilized by SRP72 binding (27,28). Our results here show that all three of these proteins visit the nucleolus and, therefore, can interact with SRP RNA.…”

Section: Discussionmentioning

confidence: 61%

“…SRP19 protein is known to bind SRP RNA independently of other SRP proteins or factors (9,30). The SRP68͞SRP72 complex from the SRP also binds SRP RNA independently from the other SRP proteins, but the interaction is stabilized by SRP19 and͞or SRP54 binding (27). When in vitro expressed proteins are studied, SRP68 binds SRP RNA before SRP72, but its binding is stabilized by SRP72 binding (27,28).…”

Section: Discussionmentioning

confidence: 99%

“…Subsequent studies demonstrated that the SRP RNA Alu domain and its associated SRP9 and SRP14 proteins constitute the translational arrest activity, whereas the S domain of SRP RNA and its associated proteins contain the nascent polypeptide signal recognition and ER docking activities, via SRP54, SRP68, and SRP72 (9,(15)(16)(17)(18)(19)(20). In vitro experiments with purified SRP components revealed that (i) SRP9 and SRP14 form a heterodimer before binding to SRP RNA, (ii) SRP19 binding to SRP RNA is required for subsequent SRP54 binding, and (iii) SRP68 binding to SRP RNA enhances SRP72 binding (9,10,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33).We recently investigated the intracellular localization of fluorescent SRP RNA after its microinjection into the nucleus of mammalian cells. We observed a rapid localization in nucleoli, followed by a gradual dissipation of nucleolar signal and the progressive appearance of fluorescence in the cytoplasm (4).…”

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confidence: 99%

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Signal recognition particle components in the nucleolus

Politz

Yarovoi

Kilroy

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

169

128

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The signal recognition particle (SRP) is a ribonucleoprotein composed of an Alu domain and an S domain. The S domain contains unique sequence SRP RNA and four SRP proteins: SRP19, SRP54, SRP68, and SRP72. SRP interacts with ribosomes to bring translating membrane and secreted proteins to the endoplasmic reticulum (ER) for proper processing. Additionally, SRP RNA is a member of a family of small nonribosomal RNAs found recently in the nucleolus, suggesting that the nucleolus is more plurifunctional than previously realized. It was therefore of interest to determine whether other SRP components localize to this intranuclear site. In transfected rat fibroblasts, green fluorescent protein fusions of SRP19, SRP68, and SRP72 localized to the nucleolus, as well as to the cytoplasm, as expected. SRP68 also accumulated in the ER, consistent with its affinity for the ER-bound SRP receptor. SRP54 was detected in the cytoplasm as a green fluorescent protein fusion and in immunofluorescence studies, but was not detected in the nucleolus. In situ hybridization experiments also revealed endogenous SRP RNA in the nucleolus. These results demonstrate that SRP RNA and three SRP proteins visit the nucleolus, suggesting that partial SRP assembly, or another unidentified activity of the SRP components, occurs at the nucleolus. SRP54 apparently interacts with nascent SRP beyond the nucleolus, consistent with in vitro reconstitution experiments showing that SRP19 must bind to SRP RNA before SRP54 binds. Our findings support the notion that the nucleolus is the site of assembly and͞or interaction between the family of ribonucleoproteins involved in protein synthesis, in addition to ribosomes themselves. T he nucleolus long has been known as a dense subnuclear structure at which ribosomal genes are clustered and ribosomal transcription, rRNA processing, and ribosomal subunit assembly occurs (1). More recently, it has become clear that the RNA components of other ribonucleoproteins also may localize to the nucleolus (2, 3), including the signal recognition particle (SRP) (4). Protein components of both RNase P and RNase MRP also recently have been shown to be localized in the nucleolus (5). The hypothesis has been advanced that the nucleolus not only has evolved to carry out ribosome synthesis but, in fact, is the site of assembly of and͞or interaction between multiple ribonucleoprotein machines, many of which are involved in protein synthesis (6). However, no information regarding the potential nucleolar localization of the other components of the SRP has been available.The SRP is a ribonucleoprotein that arrests translation of secretory or membrane proteins and docks the nascent polypeptide-ribosome complex at receptors on the endoplasmic reticulum (ER), whereupon translation is resumed to direct the protein into the membrane assembly or secretory pathways (7-9). In mammalian cells, the SRP contains six proteins (7) and an Ϸ300-nt RNA (10) that previously had been known as 7S RNA or 7SL RNA (11-13). In an early study it was found that ...

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Section: Discussionmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Signal recognition particle components in the nucleolus

Politz

Yarovoi

Kilroy

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

169

128

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“…Exposing canine SRP to high ionic strength conditions released SRP72 from the RNA as a stable heterodimer with SRP68 (Scoulica et al 1987). Early in vitro studies carried out in reticulocyte lysates suggested that SRP72 interacted with the RNA-bound SRP68 only through protein-protein interactions (Lütcke et al 1993). More recently, however, human SRP72 was shown to bind to the SRP RNA independently of SRP68 or any other SRP proteins via a 56 amino acid residue domain (Iakhiaeva et al 2005).…”

Section: Iakhiaeva Et Almentioning

confidence: 99%

The 5e motif of eukaryotic signal recognition particle RNA contains a conserved adenosine for the binding of SRP72

Iakhiaeva

Wower

et al. 2008

RNA

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The signal recognition particle (SRP) plays a pivotal role in transporting proteins to cell membranes. In higher eukaryotes, SRP consists of an RNA molecule and six proteins. The largest of the SRP proteins, SRP72, was found previously to bind to the SRP RNA. A fragment of human SRP72 (72c9) bound effectively to human SRP RNA but only weakly to the similar SRP RNA of the archaeon Methanococcus jannaschii. Chimeras between the human and M. jannaschii SRP RNAs were constructed and used as substrates for 72c9. SRP RNA helical section 5e contained the 72c9 binding site. Systematic alteration within 5e revealed that the A240G and A240C changes dramatically reduced the binding of 72c9. Human SRP RNA with a single A240G change was unable to form a complex with full-length human SRP72. Two small RNA fragments, one composed of helical section 5ef, the other of section 5e, competed equally well for the binding of 72c9, demonstrating that no other regions of the SRPR RNA were required. The biochemical data completely agreed with the nucleotide conservation pattern observed across the phylogenetic spectrum. Thus, most eukaryotic SRP RNAs are likely to require for function an adenosine within their 5e motifs. The human 5ef RNA was remarkably resistant to ribonucleolytic attack suggesting that the 240-AUC-242 ''loop'' and its surrounding nucleotides form a peculiar compact structure recognized only by SRP72.

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“…These studies have demonstrated that the SRP9/SRP14 heterodimer is required for the inhibition of translation elongation and that the SRP68/SRP72 heterodimer is involved in the interaction of SRP with SRP receptor (Siegel and Walter, 1988a;Lutcke et al, 1993;Zopf et al, 1993;Hauser et al, 1995;Thomas et al, 1997). SRP54 is the most highly conserved component of SRP and comprises two distinct domains.…”

Section: Introductionmentioning

confidence: 99%

Deletion analysis of yeast Sec65p reveals a central domain that is sufficient for function in vivo

Régnacq

Hewitt

Allen

et al. 1998

Molecular Microbiology

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SummaryThe Saccharomyces cerevisiae SEC65 gene encodes a 32 kDa subunit of yeast signal recognition particle that is homologous to human SRP19. Sequence comparisons suggest that the yeast protein comprises three distinct domains. The central domain (residues 98-171) exhibits substantial sequence similarity to the 144 residue SRP19. In contrast, the N-terminal and C-terminal domains (residues 1-97 and 172-273 respectively) share no similarity to SRP19, with the exception of a cluster of positively charged residues at the extreme C-terminus of both proteins. Here, we report the cloning of a Sec65p homologue from the yeast Candida albicans that shares the same extended domain structure as its S. cerevisiae counterpart. This conservation of sequence is reflected at the functional level, as the C. albicans gene can complement the conditional lethal sec65-1 mutation in S. cerevisiae. In order to examine the role of the N-and C-terminal domains in Sec65p function, we have engineered truncation mutants of S. cerevisiae SEC65 and tested these for complementing activity in vivo and for SRP integrity in vitro. These studies indicate that a minimal Sec65p comprising residues 76-209, which includes the entire central SRP19-like domain, is sufficient for SRP function in yeast.

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

Cited by 50 publications

References 32 publications

Signal recognition particle components in the nucleolus

Signal recognition particle components in the nucleolus

The 5e motif of eukaryotic signal recognition particle RNA contains a conserved adenosine for the binding of SRP72

Deletion analysis of yeast Sec65p reveals a central domain that is sufficient for function in vivo

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