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IPR007222 is a Signal recognition particle receptor, alpha subunit, N-terminal.
<p>This entry represents the alpha subunit of the SR receptor.</p> <p>The signal recognition particle (SRP) is a multimeric protein, which along with its conjugate receptor (SR), is involved in targeting secretory proteins to the rough endoplasmic reticulum (RER) membrane in eukaryotes, or to the plasma membrane in prokaryotes [[cite:PUB00035998], [cite:PUB00028143], [cite:PUB00100261]]. SRP recognises the signal sequence of the nascent polypeptide on the ribosome. In eukaryotes this retards its elongation until SRP docks the ribosome-polypeptide complex to the RER membrane via the SR receptor [[cite:PUB00063486], [cite:PUB00100261]]. Eukaryotic SRP consists of six polypeptides (SRP9, SRP14, SRP19, SRP54, SRP68 and SRP72) and a single 300 nucleotide 7S RNA molecule. The RNA component catalyses the interaction of SRP with its SR receptor [[cite:PUB00035999]]. In higher eukaryotes, the SRP complex consists of the Alu domain and the S domain linked by the SRP RNA. The Alu domain consists of a heterodimer of SRP9 and SRP14 bound to the 5' and 3' terminal sequences of SRP RNA. This domain is necessary for retarding the elongation of the nascent polypeptide chain, which gives SRP time to dock the ribosome-polypeptide complex to the RER membrane. In archaea, the SRP complex contains 7S RNA like its eukaryotic counterpart, yet only includes two of the six protein subunits found in the eukaryotic complex: SRP19 and SRP54 [[cite:PUB00053948]].</p> <p>The SR receptor is a monomer consisting of the loosely membrane-associated SR-alpha homologue FtsY, while the eukaryotic SR receptor is a heterodimer of SR-alpha (70kDa) and SR-beta (25kDa), both of which contain a GTP-binding domain [[cite:PUB00022264]]. SR-alpha regulates the targeting of SRP-ribosome-nascent polypeptide complexes to the translocon [[cite:PUB00036003]]. SR-alpha binds to the SRP54 subunit of the SRP complex. The SR-beta subunit is a transmembrane GTPase that anchors the SR-alpha subunit (a peripheral membrane GTPase) to the ER membrane [[cite:PUB00036002]]. SR-beta interacts with the N-terminal SRX-domain of SR-alpha, which is not present in the bacterial FtsY homologue. SR-beta also functions in recruiting the SRP-nascent polypeptide to the protein-conducting channel.</p>
This description is obtained from EB-eye REST.
GO predictions are based solely on the InterPro-to-GO mappings published by EMBL-EBI, which are in turn based on the mapping of predicted domains to the InterPro dataset. The InterPro-to-GO mapping was last updated on , while the GO metadata was last updated on .
| GO term | Namespace | Name | Definition | Relationships |
|---|---|---|---|---|
| Molecular function | GTPase activity | Catalysis of the reaction: GTP + H2O = GDP + phosphate. | ||
| Molecular function | Signal recognition particle binding | Interacting selectively and non-covalently with the signal recognition particle. | ||
| Molecular function | GTP binding | Interacting selectively and non-covalently with GTP, guanosine triphosphate. | ||
| Cellular component | Signal recognition particle receptor complex | A transmembrane heterodimeric protein located in the membrane of the rough endoplasmic reticulum. Both subunits contain GTPase domains with which signal recognition particle interacts. In the presence of GTP and SRP receptor, SRP is released from the ribosome-nascent chain complex. | ||
| Biological process | Intracellular protein transport | The directed movement of proteins in a cell, including the movement of proteins between specific compartments or structures within a cell, such as organelles of a eukaryotic cell. |
| Transcript | Name | Description | Predicted domains | Domain count |
|---|---|---|---|---|
| – | Signal recognition particle receptor subunit alpha [Medicago truncatula] gi|357480047|ref|XP_003610309.1| | 26 | ||
| – | PREDICTED: signal recognition particle receptor subunit alpha-like [Glycine max] gi|356517002|ref|XP_003527179.1| | 20 | ||
| – | Signal recognition particle receptor subunit alpha; TAIR: AT4G30600.1 signal recognition particle receptor alpha subunit family protein; Swiss-Prot: sp|A7SFP1|SHOC2_NEMVE Leucine-rich repeat protein soc-2 homolog; TrEMBL-Plants: tr|A0A1J7I2S1|A0A1J7I2S1_LUPAN Uncharacterized protein; Found in the gene: LotjaGi3g1v0241100_LC | 3 | ||
| – | Signal recognition particle protein; TAIR: AT4G30600.1 signal recognition particle receptor alpha subunit family protein; Swiss-Prot: sp|Q9DBG7|SRPRA_MOUSE Signal recognition particle receptor subunit alpha; TrEMBL-Plants: tr|G7JGN9|G7JGN9_MEDTR Signal recognition particle receptor protein, putative; Found in the gene: LotjaGi4g1v0288400 | 31 | ||
| – | Signal recognition particle protein; TAIR: AT4G30600.1 signal recognition particle receptor alpha subunit family protein; Swiss-Prot: sp|Q9DBG7|SRPRA_MOUSE Signal recognition particle receptor subunit alpha; TrEMBL-Plants: tr|G7JGN9|G7JGN9_MEDTR Signal recognition particle receptor protein, putative; Found in the gene: LotjaGi4g1v0288400 | 30 | ||
| – | Signal recognition particle protein; TAIR: AT4G30600.1 signal recognition particle receptor alpha subunit family protein; Swiss-Prot: sp|Q9DBG7|SRPRA_MOUSE Signal recognition particle receptor subunit alpha; TrEMBL-Plants: tr|A0A1J7GDN0|A0A1J7GDN0_LUPAN Uncharacterized protein; Found in the gene: LotjaGi6g1v0202600 | 26 | ||
| – | Signal recognition particle protein; TAIR: AT4G30600.1 signal recognition particle receptor alpha subunit family protein; Swiss-Prot: sp|Q9DBG7|SRPRA_MOUSE Signal recognition particle receptor subunit alpha; TrEMBL-Plants: tr|A0A1J7GDN0|A0A1J7GDN0_LUPAN Uncharacterized protein; Found in the gene: LotjaGi6g1v0202600 | 26 |
A list of co-occurring predicted domains within the L. japonicus gene space:
| Predicted domain | Source | Observations | Saturation (%) |
|---|---|---|---|
| mobidb-lite | MobiDBLite | 1 | 14.29 |