SRP receptor SRP receptor:SRP:ribosome:polypeptide+signal Translocon:TRAP polypeptide+signal:Translocon Signal Recognition Particle Translocation of signal-containing nascent peptide to Endoplasmic Reticulum Authored: May, B, Gopinathrao, G, 2008-11-19 19:22:37 Edited: May, B, Gopinathrao, G, 2008-11-19 19:22:37 Pubmed11964406 Pubmed18166647 Pubmed9631292 Reactome Database ID Release 431799326 Reactome, http://www.reactome.org ReactomeREACT_115582 Reviewed: D'Eustachio, P, Matthews, L, Gillespie, ME, 2008-12-02 16:25:31 The Signal Recognition Particle (SRP) receptor mediates transfer of the ribosome:mRNA:nascent protein complex to the Translocon Complex. A coupled reaction (not annotated here) in which GTP molecules are hydrolyzed by the alpha subunit of the SRP Receptor and the SRP54 subunit of the SRP is thought to ensure release of the SRP only after the ribosome is properly reoriented. At the end of this process, the ribosome is attached to the endoplasmic reticulum (ER) membrane with its associated nascent polypeptide protruding through the Translocon Complex into the ER lumen.