Macrophage-expressed gene 1 protein (MPEG1)

Macrophage-expressed gene 1 protein (MPEG1, also known as Perforin-2) is a type I transmembrane protein that belongs to the Membrane Attack Complex/Perforin (MACPF) superfamily of pore-forming proteins, playing a crucial role in the innate immune defense against intracellular bacteria[1][2]. MPEG1 is constitutively expressed in macrophages and other phagocytes, and its expression can be induced in non-immune cells by pro-inflammatory signals such as TNFα and LPS[1][2]. Structurally, MPEG1 contains an N-terminal MACPF domain, a multi-vesicular body-12-associated β-prism (MABP) domain, a transmembrane region, and a cytosolic tail[1]. MPEG1 traffics to early endosomes, phagosomes, and phagolysosomes, where it oligomerizes and, upon acidification, forms large transmembrane pores in phagocytosed microbes, leading to their destruction[1][2]. Genetic mutations in MPEG1 have been associated with increased susceptibility to chronic intracellular infections, highlighting its role as an intracellular immune effector. No drugs are currently known to target MPEG1 directly, and the primary therapeutic relevance is its crucial function in antimicrobial immunity and potential as a biomarker or genetic risk factor for certain infections[1][2].

Other names

Perforin-2PRF2Mpg-1P-2MPS1IMD77macrophage expressed gene 1macrophage gene 1 proteinmacrophage-expressed gene 1 protein

Forms oligomeric prepores and acid-activated pores to disrupt the membranes of engulfed microbial pathogens[1][2]; Localizes to phagosomes and phagolysosomes, mediating antimicrobial activity via pore formation[2]; Upregulation regulated by inflammatory stimuli (e.g., TNFα, LPS)[1]