Flavivirus pre-membrane protein M (prM protein, sometimes abbreviated as prM/M or M protein in mature virions)

The Flavivirus pre-membrane protein M (prM protein) is a structural protein produced by cleavage of the viral polyprotein in the endoplasmic reticulum of infected cells. In immature virions, prM forms heterodimers with the envelope E protein, acting as a chaperone to ensure correct folding and to mask the fusion peptide of E, thereby preventing premature activation of membrane fusion. Upon passage through the secretory pathway, prM is cleaved by the host protease furin, releasing the pr fragment and leaving the M protein, which helps stabilize the mature, fusion-competent structure of the virion. The prM/E interface and its processing are critical for infectivity, and both the prM protein and its remnants are major targets in vaccine development and antibody therapeutics. Disruption or misregulation of prM cleavage can result in the production of non-infectious or fusion-inactive virus particles. The prM protein is also implicated in pathogenic processes such as antibody-dependent enhancement, making its accurate inclusion and targeting essential for safe vaccine strategies.

Other names

Pre-membrane proteinprM proteinM protein (after furin cleavage/maturation)pr peptide (the cleaved N-terminal fragment)

Block maturation—Interfere with prM-E heterodimer formation or furin-mediated cleavage to prevent infectious virus formation. Prevent fusion—Stabilize prM-E interaction, preventing structural rearrangements necessary for membrane fusion. Induce immune response—Present prM/E epitopes in vaccine formulations for protective immunity.