Signal recognition particle
349467
201006012
2008-03-26T06:58:38Z
DumZiBoT
6085301
Bot: Converting bare references, see [[User:DumZiBoT/refLinks|FAQ]]
__NOTOC__
{{protein
| Name = signal recognition particle 9kDa
| caption =
| image =
| width =
| HGNCid = 11304
| Symbol = SRP9
| AltSymbols =
| EntrezGene = 6726
| OMIM = 600707
| RefSeq = NM_003133
| UniProt = P49458
| PDB =
| ECnumber =
| Chromosome = 1
| Arm = q
| Band = 42.12
| LocusSupplementaryData =
}}
{{protein
| Name = signal recognition particle 14kDa
| caption =
| image =
| width =
| HGNCid = 11299
| Symbol = SRP14
| AltSymbols =
| EntrezGene = 6727
| OMIM = 600708
| RefSeq = NM_003134
| UniProt = P37108
| PDB =
| ECnumber =
| Chromosome = 15
| Arm = q
| Band = 22
| LocusSupplementaryData =
}}
{{protein
| Name = signal recognition particle 19kDa
| caption =
| image =
| width =
| HGNCid = 11300
| Symbol = SRP19
| AltSymbols =
| EntrezGene = 6728
| OMIM = 182175
| RefSeq = NM_003135
| UniProt = P09132
| PDB =
| ECnumber =
| Chromosome = 5
| Arm = q
| Band = 21
| LocusSupplementaryData = -q22
}}
{{protein
| Name = signal recognition particle 54kDa
| caption =
| image =
| width =
| HGNCid = 11301
| Symbol = SRP54
| AltSymbols =
| EntrezGene = 6729
| OMIM = 604857
| RefSeq = NM_003136
| UniProt = P61011
| PDB =
| ECnumber =
| Chromosome = 14
| Arm = q
| Band = 13.2
| LocusSupplementaryData =
}}
{{protein
| Name = signal recognition particle 68kDa
| caption =
| image =
| width =
| HGNCid = 11302
| Symbol = SRP68
| AltSymbols =
| EntrezGene = 6730
| OMIM = 604858
| RefSeq = NM_014230
| UniProt = Q9UHB9
| PDB =
| ECnumber =
| Chromosome = 17
| Arm = q
| Band = 25.1
| LocusSupplementaryData =
}}
{{protein
| Name = signal recognition particle 72kDa
| caption =
| image =
| width =
| HGNCid = 11303
| Symbol = SRP72
| AltSymbols =
| EntrezGene = 6731
| OMIM = 602122
| RefSeq = NM_006947
| UniProt = O76094
| PDB =
| ECnumber =
| Chromosome = 4
| Arm = q
| Band = 11
| LocusSupplementaryData =
}}
The '''signal recognition particle''' (SRP) is a [[ribonucleoprotein]] ([[protein]]-[[RNA]] complex) that recognizes and transports specific proteins to the [[endoplasmic reticulum]] in [[eukaryote]]s and the [[plasma membrane]] in [[prokaryote]]s. The eukaryotic SRP is composed of six distinct [[polypeptides]] bound to an RNA molecule (the [[7SL RNA]]), with [[GTPase]] activity. In the [[Guanosine triphosphate|GTP]]-bound state, it recognizes an endoplasmic reticulum signal sequence of eight or more [[nonpolar]] [[amino acid]] residues at its center.<ref>[http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=mboc4,Signal%20Recognition%20Particle&rid=mboc4.section.2202#2213 MBOC4 at NCB]</ref> It transiently binds to the [[endoplasmic reticulum]] [[signal sequence]] in a [[nascent]] protein, to the large [[ribosome|ribosomal]] unit, and to the [[SRP receptor]]. The core of the SRP is universal, being conserved in all three [[Kingdom (biology)|kingdoms]].
The SRP is found in the [[cytosol]]. In [[eukaryotes]], it binds to the endoplasmic reticulum [[signal sequence]] found in an emerging secretory protein and subsequently delivers the protein along with the [[ribosome]] to the membrane of the endoplasmic reticulum. When SRP binds the endoplasmic reticulum signal sequence, it also binds the [[ribosome]] and thereby pauses translation until the entire SRP-bound translation complex is transported to the endoplasmic reticulum, where [[translation (genetics)|translation]] resumes.
SRP and its receptor initiate the transfer of the [[nascent]] chain across the endoplasmic reticulum membrane. Once the chain reaches the [[translocon]], SRP and its receptor both hydrolyze their bound [[Guanosine triphosphate|GTP]] to [[Guanosine diphosphate|GDP]], then dislocate allowing translation to restart.
==Components==
*P9
*P14
*P19
*P54
*P68
*P72
*SRP RNA
==History==
SRP was identified and characterized by [[Peter Walter]] when he was a graduate student in the laboratory of [[Günter Blobel]].<ref>[http://www.jcb.org/cgi/content/full/171/1/13 Isolating SRP - Leslie 171 (1): 13 - The Journal of Cell Biology<!-- Bot generated title -->]</ref>
==References==
<references/>
==External links==
* {{MeshName|Signal+Recognition+Particle}}
* [http://rnp.uthct.edu/ Signal Recognition Particle Database]
* [http://nobelprize.org/nobel_prizes/medicine/laureates/1999/index.html The Nobel Prize in Physiology or Medicine 1999], "for the discovery that proteins have intrinsic signals that govern their transport and localization in the cell" to Günter Blobel, USA. Press Release, Illustrated Presentation, Presentation Speech
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[[Category:Cell signaling]]
[[de:Signal Recognition Particle]]
[[en:Partícula de reconocimiento de señal]]
[[it:Signal recognition particle]]