Abstract:Protein is one of the most important biological macromolecules. In the protein translocation system, many proteins, after being synthesized in the ribosome, will enter their corresponding subcellular organelles through the endoplasmic reticulum or plasma membrane to play a important role in biological functions. There are three pathways for protein secretion, which are Sec pathway, Tat pathway and SRP pathway. In this paper, we present a basic transport pathway of protein, and mainly introduce the translocation mediated by the signal recognition particle. We summarize the composition and function of the signal recognition particle and its receptor respectively, and also make a brief explanation about the regulation pathway. What’s more, we introduce the relevant YidC membrane protein family, and we also have a new insight into the existent of the signal recognition particle regulatory system.