Signal recognition particle( SRP)-- a particle composed of proteins and7 SL RNA that binds to signal sequences and targets polypeptide chains to the endoplasmic reticulum.

• 讯息（挥）列--蛋白质末端的一段疏水性氨基酸，在细菌中引导蛋白质分泌或在真核细胞中将蛋白质并入内质网。