What is Signal recognition particle?
The '''signal recognition particle''' ('''SRP''') is a common molecule found in [[cytoplasm]]. It is a ''ribonucleoprotein'' (a [[protein]]-[[RNA]] complex). It recognizes and targets specific proteins to the [[endoplasmic reticulum]] of [[eukaryote]]s and the [[plasma membrane]] of [[prokaryote]]s.<ref>Abell BM ''et al'' 2004. Signal recognition particle mediates post-translational targeting in eukaryotes. ''EMBO Journal''. '''23''' (14): 2755–64.[https://www.emboj.embopress.org/content/23/14/2755] {{Webarchive|url=https://web.archive.org/web/20180602173640/http://emboj.embopress.org/content/23/14/2755 |date=2018-06-02 }}</ref> When the SRP-ribosome complex binds to a cell membrane receptor, SRP releases the ribosome and drifts away. The ribosome resumes [[protein synthesis]], but now the protein is moving through the SRP-receptor transmembrane [[pore]]. So, SRP directs the movement of proteins within the cell. It binds with a transmembrane pore. This allows the protein to cross the membrane to where it is needed. In [[eukaryotes]], the target is the membrane of the [[endoplasmic reticulum]] (ER). The SRP is 'universally conserved'. That means it is so important that ''all living things have it in their cells''.<ref>Batey RT, Sagar MB & Doudna JA 2001. Structural and energetic analysis of RNA recognition by a universally conserved protein from the signal recognition particle. ''Journal of Molecular Biology''. '''307''' (1): 229–46. [https://www.sciencedirect.com/science/article/pii/S0022283600944541?via%3Dihub ]</ref> Despite this, the actual composition of the SRP varies greatly between organisms.<ref>Rosenblad MA, Larsen N, Samuelsson T, Zwieb C 2009. Kinship in the SRP RNA family. ''RNA Biology'' '''6''' (5): 508–16. [https://www.tandfonline.com/doi/abs/10.4161/rna.6.5.9753]</ref> == References == {{reflist}} [[Category:Cell biology]]