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 {{Cell-biology-stub}} {{biochem-stub}} [[Category:Cell signaling]] [[de:Signal Recognition Particle]] [[en:Partícula de reconocimiento de señal]] [[it:Signal recognition particle]]