Signal recognition particle
| signal recognition particle 9kDa | |
|---|---|
| Identifiers | |
| Symbol | SRP9 |
| Entrez | 6726 |
| HUGO | 11304 |
| OMIM | 600707 |
| RefSeq | NM_003133 |
| UniProt | P49458 |
| Other data | |
| Locus | Chr. 1 q42.12 |
| signal recognition particle 14kDa | |
|---|---|
| Identifiers | |
| Symbol | SRP14 |
| Entrez | 6727 |
| HUGO | 11299 |
| OMIM | 600708 |
| RefSeq | NM_003134 |
| UniProt | P37108 |
| Other data | |
| Locus | Chr. 15 q22 |
| signal recognition particle 19kDa | |
|---|---|
| Identifiers | |
| Symbol | SRP19 |
| Entrez | 6728 |
| HUGO | 11300 |
| OMIM | 182175 |
| RefSeq | NM_003135 |
| UniProt | P09132 |
| Other data | |
| Locus | Chr. 5 q21-q22 |
| signal recognition particle 54kDa | |
|---|---|
| Identifiers | |
| Symbol | SRP54 |
| Entrez | 6729 |
| HUGO | 11301 |
| OMIM | 604857 |
| RefSeq | NM_003136 |
| UniProt | P61011 |
| Other data | |
| Locus | Chr. 14 q13.2 |
| signal recognition particle 68kDa | |
|---|---|
| Identifiers | |
| Symbol | SRP68 |
| Entrez | 6730 |
| HUGO | 11302 |
| OMIM | 604858 |
| RefSeq | NM_014230 |
| UniProt | Q9UHB9 |
| Other data | |
| Locus | Chr. 17 q25.1 |
| signal recognition particle 72kDa | |
|---|---|
| Identifiers | |
| Symbol | SRP72 |
| Entrez | 6731 |
| HUGO | 11303 |
| OMIM | 602122 |
| RefSeq | NM_006947 |
| UniProt | O76094 |
| Other data | |
| Locus | Chr. 4 q11 |
The signal recognition particle (SRP) is an abundant, cytosolic, universally conserved ribonucleoprotein (protein-RNA complex) that recognizes and targets specific proteins to the endoplasmic reticulum in eukaryotes and the plasma membrane in prokaryotes.
The function of SRP was discovered by the study of processed and unprocessed immunoglobulin light chains; newly synthesized proteins in eukaryotes carry N-terminal hydrophobic signal sequences, which are bound by SRP when they emerge from the ribosome.
In eukaryotes, SRP binds to the signal sequence of a newly synthesized peptide as it emerges from the ribosome. This binding leads to the slowing of protein synthesis known as "elongation arrest," a conserved function of SRP that facilitates the coupling of the protein translation and the protein translocation processes. SRP then targets this entire complex (the ribosome-nascent chain complex) to the protein-conducting channel, also known as the translocon, in the ER (Endoplasmic reticulum) membrane. This occurs via the interaction and docking of SRP with its cognate SRP receptor that is located in close proximity to the translocon.
In eukaryotes there are three domains between SRP and its receptor that function in guanosine triphosphate (GTP) binding and hydrolysis. These are located in two related subunits in the SRP receptor (SRα and SRβ) and the SRP protein SRP54 (known as Ffh in bacteria). The coordinated binding of GTP by SRP and the SRP receptor has been shown to be a prerequisite for the successful targeting of SRP to the SRP receptor.
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Wikipedia