MPEG1

Macrophage Expressed Protein 1 (MPEG1), also known as CD300LG or CD300e, is a transmembrane glycoprotein primarily expressed in myeloid cells, including macrophages and dendritic cells. It modulates innate immune responses by regulating phagocytosis and inflammatory cytokine production, contributing to tissue homeostasis and pathogen clearance.
Mechanistically, MPEG1 contains an immunoglobulin-like domain that interacts with cell surface ligands, triggering downstream signaling through adaptor proteins like Syk kinase, thereby activating NF-κB and MAPK pathways. Dysregulation of MPEG1 is linked to chronic inflammatory disorders, such as rheumatoid arthritis and atherosclerosis, where excessive macrophage activation exacerbates tissue damage. Current drug development focuses on targeting MPEG1 to fine-tune macrophage polarization, with preclinical studies exploring its potential as a therapeutic axis for immune-mediated diseases.