Signal peptide peptidase (SPP) is a type of transmembrane protease belonging to the intramembrane proteolytic enzyme family, primarily functioning to recognize and cleave transmembrane signal peptides. SPP's structure includes a transmembrane region with an active site, specifically targeting proteins. It is located in the endoplasmic reticulum membrane, involved in the post-translational modification and quality control of proteins, affecting their localization and function. The gene expression of SPP is cell-specific, related to various physiological and pathological processes. Changes or mutations in its expression may lead to cellular dysfunction, associated with the development of certain diseases.