scholarly journals SRP19 Is a Dispensable Component of the Signal Recognition Particle in Archaea

2006 ◽  
Vol 189 (1) ◽  
pp. 276-279 ◽  
Author(s):  
Sophie Yurist ◽  
Idit Dahan ◽  
Jerry Eichler
Keyword(s):  
Cell Growth ◽  
Membrane Protein ◽  
Protein Secretion ◽  
Signal Recognition Particle ◽  
Haloferax Volcanii ◽  
Signal Recognition ◽  
Protein Insertion ◽  
Membrane Protein Insertion ◽  
Srp Rna

ABSTRACT In vitro, archaeal SRP54 binds SRP RNA in the absence of SRP19, suggesting the latter to be expendable in Archaea. Accordingly, the Haloferax volcanii SRP19 gene was deleted. Although normally transcribed at a level comparable to that of the essential SRP54 gene, SRP19 deletion had no effect on cell growth, membrane protein insertion, protein secretion, or ribosome levels. The absence of SRP19 did, however, increase membrane bacterioruberin levels.

scholarly journals In Vivo Analysis of an Essential Archaeal Signal Recognition Particle in Its Native Host

2002 ◽  
Vol 184 (12) ◽  
pp. 3260-3267 ◽  
Author(s):  
R. Wesley Rose ◽  
Mechthild Pohlschröder
Keyword(s):  
Protein Targeting ◽  
Protein Translocation ◽  
Signal Recognition Particle ◽  
Signal Recognition ◽  
Sequence Comparisons ◽  
Protein Insertion ◽  
Native Host

ABSTRACT The evolutionarily conserved signal recognition particle (SRP) plays an integral role in Sec-mediated cotranslational protein translocation and membrane protein insertion, as it has been shown to target nascent secretory and membrane proteins to the bacterial and eukaryotic translocation pores. However, little is known about its function in archaea, since characterization of the SRP in this domain of life has thus far been limited to in vitro reconstitution studies of heterologously expressed archaeal SRP components identified by sequence comparisons. In the present study, the genes encoding the SRP54, SRP19, and 7S RNA homologs (hv54h, hv19h, and hv7Sh, respectively) of the genetically and biochemically tractable archaeon Haloferax volcanii were cloned, providing the tools to analyze the SRP in its native host. As part of this analysis, an hv54h knockout strain was created. In vivo characterization of this strain revealed that the archaeal SRP is required for viability, suggesting that cotranslational protein translocation is an essential process in archaea. Furthermore, a method for the purification of this SRP employing nickel chromatography was developed in H. volcanii, allowing the successful copurification of (i) Hv7Sh with a histidine-tagged Hv54h, as well as (ii) Hv54h and Hv7Sh with a histidine-tagged Hv19h. These results provide the first in vivo evidence that these components interact in archaea. Such copurification studies will provide insight into the significance of the similarities and differences of the protein-targeting systems of the three domains of life, thereby increasing knowledge about the recognition of translocated proteins in general.

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

1990 ◽  
Vol 10 (2) ◽  
pp. 777-784
Author(s):  
K Strub ◽  
P Walter
Keyword(s):  
Cdna Clone ◽  
Repetitive Sequences ◽  
Signal Recognition Particle ◽  
Secretory Proteins ◽  
Endoplasmic Reticulum Membrane ◽  
Cdna Clones ◽  
Functional Domain ◽  
Signal Recognition ◽  
Srp Rna

The signal recognition particle (SRP), a cytoplasmic ribonucleoprotein, plays an essential role in targeting secretory proteins to the rough endoplasmic reticulum membrane. In addition to the targeting function, SRP contains an elongation arrest or pausing function. This function is carried out by the Alu domain, which consists of two proteins, SRP9 and SRP14, and the portion of SRP (7SL) RNA which is homologous to the Alu family of repetitive sequences. To study the assembly pathway of the components in the Alu domain, we have isolated a cDNA clone of SRP9, in addition to a previously obtained cDNA clone of SRP14. We show that neither SRP9 nor SRP14 alone interacts specifically with SRP RNA. Rather, the presence of both proteins is required for the formation of a stable RNA-protein complex. Furthermore, heterodimerization of SRP9 and SRP14 occurs in the absence of SRP RNA. Since a partially reconstituted SRP lacking SRP9 and SRP14 [SRP(-9/14)] is deficient in the elongation arrest function, it follows from our results that both proteins are required to assemble a functional domain. In addition, SRP9 and SRP14 synthesized in vitro from synthetic mRNAs derived from their cDNA clones restore elongation arrest activity to SRP(-9/14).

scholarly journals F1F0 ATP synthase subunit c is a substrate of the novel YidC pathway for membrane protein biogenesis

2004 ◽  
Vol 165 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Martin van der Laan ◽  
Philipp Bechtluft ◽  
Stef Kol ◽  
Nico Nouwen ◽  
Arnold J.M. Driessen
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Atp Synthase ◽  
Signal Recognition Particle ◽  
Membrane Vesicles ◽  
Membrane Insertion ◽  
Subunit C ◽  
Protein Insertion ◽  
F1f0 Atp Synthase

The Escherichia coli YidC protein belongs to the Oxa1 family of membrane proteins that have been suggested to facilitate the insertion and assembly of membrane proteins either in cooperation with the Sec translocase or as a separate entity. Recently, we have shown that depletion of YidC causes a specific defect in the functional assembly of F1F0 ATP synthase and cytochrome o oxidase. We now demonstrate that the insertion of in vitro–synthesized F1F0 ATP synthase subunit c (F0c) into inner membrane vesicles requires YidC. Insertion is independent of the proton motive force, and proteoliposomes containing only YidC catalyze the membrane insertion of F0c in its native transmembrane topology whereupon it assembles into large oligomers. Co-reconstituted SecYEG has no significant effect on the insertion efficiency. Remarkably, signal recognition particle and its membrane-bound receptor FtsY are not required for the membrane insertion of F0c. In conclusion, a novel membrane protein insertion pathway in E. coli is described in which YidC plays an exclusive role.

scholarly journals Signal recognition particle protein 19 is imported into the nucleus by importin 8 (RanBP8) and transportin

2001 ◽  
Vol 114 (19) ◽  
pp. 3479-3485 ◽  
Author(s):  
Kellie A. Dean ◽  
Oliver von Ahsen ◽  
Dirk Görlich ◽  
Howard M. Fried
Keyword(s):  
Signal Recognition Particle ◽  
Signal Recognition ◽  
Protein Subunit ◽  
Animal Cells ◽  
Nuclear Assembly ◽  
Cytoplasmic Rna ◽  
Cytoplasmic Transport ◽  
Transport Receptors ◽  
Srp Rna

The signal recognition particle (SRP) is a cytoplasmic RNA-protein complex that targets proteins to the rough endoplasmic reticulum. Although SRP functions in the cytoplasm, RNA microinjection and cDNA transfection experiments in animal cells, as well as genetic analyses in yeast, have indicated that SRP assembles in the nucleus. Nonetheless, the mechanisms responsible for nuclear-cytoplasmic transport of SRP RNA and SRP proteins are largely unknown. Here we show that the 19 kDa protein subunit of mammalian SRP, SRP19, was efficiently imported into the nucleus in vitro by two members of the importin β superfamily of transport receptors, importin 8 and transportin; SRP19 was also imported less efficiently by several other members of the importin β family. Although transportin is known to import a variety of proteins, SRP19 import is the first function assigned to importin 8. Furthermore, we show that a significant pool of endogenous SRP19 is located in the nucleus, as well as the nucleolus. Our results show that at least one mammalian SRP protein is specifically imported into the nucleus, by members of the importin β family of transport receptors, and the findings add additional evidence for nuclear assembly of SRP.

scholarly journals Polynucleotide Phosphorylase, RNase E/G, and YbeY Are Involved in the Maturation of 4.5S RNA in Corynebacterium glutamicum

2016 ◽  
Vol 199 (5) ◽  
Author(s):  
Tomoya Maeda ◽  
Yuya Tanaka ◽  
Masaaki Wachi ◽  
Masayuki Inui
Keyword(s):  
Membrane Protein ◽  
Corynebacterium Glutamicum ◽  
Signal Recognition Particle ◽  
Membrane Insertion ◽  
Signal Recognition ◽  
Rnase E ◽  
Content Type ◽  
Domains Of Life ◽  
4.5S Rna ◽  
Srp Rna

ABSTRACT Corynebacterium glutamicum has been applied for the industrial production of various metabolites, such as amino acids. To understand the biosynthesis of the membrane protein in this bacterium, we investigated the process of signal recognition particle (SRP) assembly. SRP is found in all three domains of life and plays an important role in the membrane insertion of proteins. SRP RNA is initially transcribed as precursor molecules; however, relatively little is known about its maturation. In C. glutamicum, SRP consists of the Ffh protein and 4.5S RNA lacking an Alu domain. In this study, we found that 3′-to-5′ exoribonuclease, polynucleotide phosphorylase (PNPase), and two endo-type RNases, RNase E/G and YbeY, are involved in the 3′ maturation of 4.5S RNA in C. glutamicum. The mature form of 4.5S RNA was inefficiently formed in ΔrneG Δpnp mutant cells, suggesting the existence of an alternative pathway for the 3′ maturation of 4.5S RNA. Primer extension analysis also revealed that the 5′ mature end of 4.5S RNA corresponds to that of the transcriptional start site. Immunoprecipitated Ffh protein contained immature 4.5S RNA in Δpnp, ΔrneG, and ΔybeY mutants, suggesting that 4.5S RNA precursors can interact with Ffh. These results imply that the maturation of 4.5S RNA can be performed in the 4.5S RNA-Ffh complex. IMPORTANCE Overproduction of a membrane protein, such as a transporter, is useful for engineering of strains of Corynebacterium glutamicum, which is a workhorse of amino acid production. To understand membrane protein biogenesis in this bacterium, we investigated the process of signal recognition particle (SRP) assembly. SRP contains the Ffh protein and SRP RNA and plays an important role in the membrane insertion of proteins. Although SRP RNA is highly conserved among the three domains of life, relatively little is known about its maturation. We show that PNPase, RNase E/G, and YbeY are involved in the 3′ maturation of the SRP RNA (4.5S RNA) in this bacterium. This indicates that 3′ end processing in this organism is different from that in other bacteria, such as Escherichia coli.

scholarly journals Membrane protein insertion and assembly by the bacterial holo-translocon SecYEG–SecDF–YajC–YidC

2016 ◽  
Vol 473 (19) ◽  
pp. 3341-3354 ◽  
Author(s):  
Joanna Komar ◽  
Sara Alvira ◽  
Ryan J. Schulze ◽  
Remy Martin ◽  
Jelger A. Lycklama a Nijeholt ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Signal Recognition Particle ◽  
Common Mechanism ◽  
Membrane Insertion ◽  
Transmembrane Helices ◽  
Protein Insertion ◽  
Wide Range ◽  
Membrane Protein Insertion ◽  
Bona Fide ◽  
Lateral Gate

Protein secretion and membrane insertion occur through the ubiquitous Sec machinery. In this system, insertion involves the targeting of translating ribosomes via the signal recognition particle and its cognate receptor to the SecY (bacteria and archaea)/Sec61 (eukaryotes) translocon. A common mechanism then guides nascent transmembrane helices (TMHs) through the Sec complex, mediated by associated membrane insertion factors. In bacteria, the membrane protein ‘insertase’ YidC ushers TMHs through a lateral gate of SecY to the bilayer. YidC is also thought to incorporate proteins into the membrane independently of SecYEG. Here, we show the bacterial holo-translocon (HTL) — a supercomplex of SecYEG–SecDF–YajC–YidC — is a bona fide resident of the Escherichia coli inner membrane. Moreover, when compared with SecYEG and YidC alone, the HTL is more effective at the insertion and assembly of a wide range of membrane protein substrates, including those hitherto thought to require only YidC.

scholarly journals 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.

1990 ◽  
Vol 10 (2) ◽  
pp. 777-784 ◽  
Author(s):  
K Strub ◽  
P Walter
Keyword(s):  
Cdna Clone ◽  
Repetitive Sequences ◽  
Signal Recognition Particle ◽  
Secretory Proteins ◽  
Endoplasmic Reticulum Membrane ◽  
Cdna Clones ◽  
Functional Domain ◽  
Signal Recognition ◽  
Srp Rna

The signal recognition particle (SRP), a cytoplasmic ribonucleoprotein, plays an essential role in targeting secretory proteins to the rough endoplasmic reticulum membrane. In addition to the targeting function, SRP contains an elongation arrest or pausing function. This function is carried out by the Alu domain, which consists of two proteins, SRP9 and SRP14, and the portion of SRP (7SL) RNA which is homologous to the Alu family of repetitive sequences. To study the assembly pathway of the components in the Alu domain, we have isolated a cDNA clone of SRP9, in addition to a previously obtained cDNA clone of SRP14. We show that neither SRP9 nor SRP14 alone interacts specifically with SRP RNA. Rather, the presence of both proteins is required for the formation of a stable RNA-protein complex. Furthermore, heterodimerization of SRP9 and SRP14 occurs in the absence of SRP RNA. Since a partially reconstituted SRP lacking SRP9 and SRP14 [SRP(-9/14)] is deficient in the elongation arrest function, it follows from our results that both proteins are required to assemble a functional domain. In addition, SRP9 and SRP14 synthesized in vitro from synthetic mRNAs derived from their cDNA clones restore elongation arrest activity to SRP(-9/14).

scholarly journals Genetic Screen Yields Mutations in Genes Encoding All Known Components of the Escherichia coli Signal Recognition Particle Pathway

2002 ◽  
Vol 184 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Hongping Tian ◽  
Jon Beckwith
Keyword(s):  
Escherichia Coli ◽  
Signal Recognition Particle ◽  
Genetic Screen ◽  
Signal Recognition ◽  
Protein Insertion ◽  
E Coli ◽  
Genes Encoding ◽  
Membrane Protein Insertion ◽  
4.5S Rna ◽  
Distinct Membrane

ABSTRACT We describe the further utilization of a genetic screen that identifies mutations defective in the assembly of proteins into the Escherichia coli cytoplasmic membrane. The screen yielded mutations in each of the known genes encoding components of the E. coli signal recognition particle pathway: ffh, ffs, and ftsY, which encode Ffh, 4.5S RNA, and FtsY, respectively. In addition, the screen yielded mutations in secM, which is involved in regulating levels of the SecA component of the bacterium’s protein export pathway. We used a sensitive assay involving biotinylation to show that all of the mutations caused defects in the membrane insertions of three topologically distinct membrane proteins, AcrB, MalF, and FtsQ. Among the mutations that resulted in membrane protein insertion defects, only the secM mutations also showed defects in the translocation of proteins into the E. coli periplasm. Genetic evidence suggests that the S382T alteration of Ffh affects the interaction between Ffh and 4.5S RNA.

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