SRP54/YPR088C Summary Help

Standard Name SRP54
Systematic Name YPR088C
Alias SRH1
Feature Type ORF, Verified
Description Signal recognition particle (SRP) subunit (homolog of mammalian SRP54); contains the signal sequence-binding activity of SRP, interacts with the SRP RNA, and mediates binding of SRP to signal receptor; contains GTPase domain (1 and see Summary Paragraph)
Name Description Signal Recognition Particle
Chromosomal Location
ChrXVI:713028 to 711403 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All SRP54 GO evidence and references
  View Computational GO annotations for SRP54
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 5 genes
Classical genetics
Large-scale survey
reduction of function
50 total interaction(s) for 25 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 35
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 2
  • Co-fractionation: 1
  • Co-purification: 2
  • Reconstituted Complex: 2
  • Two-hybrid: 2

Genetic Interactions
  • Dosage Rescue: 2
  • Negative Genetic: 2
  • Positive Genetic: 1

Expression Summary
Length (a.a.) 541
Molecular Weight (Da) 59,624
Isoelectric Point (pI) 9.04
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXVI:713028 to 711403 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1626 713028..711403 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000006292

The signal recognition particle (SRP) is an abundant and conserved ribonucleoprotein necessary for targeting proteins to the endoplasmic reticulum membrane (2). SRP in eukaryotes contains six subunits and a 7S RNA molecule; in S. cerevisiae the subunits are encoded by SRP14, SRP21, SRP68, SRP72, SEC65, and SRP54, and the RNA (termed scR1) is encoded by SCR1 (2, 3). With the exception of Srp54p, the proteins and RNA assemble into a core complex in the nucleus; this particle is exported to the cytoplasm where Srp54p joins to form the complete complex (4). Sec65p is required for association of Srp54p with the SRP particle (5). Loss of any of the SRP components causes a slow growth phenotype and loss of SRP-mediated translocation, but not cell death, indicating that the signal recognition particle is not essential in yeast and SRP-independent translocation can occur (2, 3).

The first step of SRP-mediated cotranslational targeting is interaction between SRP and the ribosome nascent chain complex (RNC), which is comprised of the translating ribosome and the emerging nascent protein. SRP interacts with the RNC through the N-terminal hydrophobic signal sequence of the nascent protein. SRP then directs the RNC to the ER membrane via interaction between SRP and a signal receptor complex (SR), encoded by SRP101 and SRP102. Finally, the RNC is transferred to the translocon, a protein-conducting membrane channel, and SRP and the SR dissociate. GTP binding by both SRP (via the Srp54p subunit) and the SR is critical for their interaction, and GTP hydrolysis facilitates their dissociation (reviewed in 6, and see 6 for more details).

Biochemical analyses of the mammalian protein indicate that Srp54p contains the following domains: an N-terminal four-helix bundle (N domain), a central GTP binding consensus sequence (G domain), and a C-terminal methionine-rich domain (M domain). The N and G domains are involved in the GTP-dependent interaction with SR, while the M domain binds the 7S RNA and mediates the binding of SRP to the signal peptide (7, 8, reviewed in 6).

Last updated: 2008-08-11 Contact SGD

References cited on this page View Complete Literature Guide for SRP54
1) Ogg SC, et al.  (1998) A functional GTPase domain, but not its transmembrane domain, is required for function of the SRP receptor beta-subunit. J Cell Biol 142(2):341-54
2) Hann BC and Walter P  (1991) The signal recognition particle in S. cerevisiae. Cell 67(1):131-44
3) Brown JD, et al.  (1994) Subunits of the Saccharomyces cerevisiae signal recognition particle required for its functional expression. EMBO J 13(18):4390-400
4) Ciufo LF and Brown JD  (2000) Nuclear export of yeast signal recognition particle lacking Srp54p by the Xpo1p/Crm1p NES-dependent pathway. Curr Biol 10(20):1256-64
5) Stirling CJ and Hewitt EW  (1992) The S. cerevisiae SEC65 gene encodes a component of yeast signal recognition particle with homology to human SRP19. Nature 356(6369):534-7
6) Wild K, et al.  (2004) SRP meets the ribosome. Nat Struct Mol Biol 11(11):1049-53
7) Zopf D, et al.  (1990) 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 9(13):4511-7
8) Hann BC, et al.  (1989) Saccharomyces cerevisiae and Schizosaccharomyces pombe contain a homologue to the 54-kD subunit of the signal recognition particle that in S. cerevisiae is essential for growth. J Cell Biol 109(6 Pt 2):3223-30