Lipase Maturation Factor 1 in Hypertriglyceridemia

This study examines the role of lipase maturation factor 1 (LMF1) as a critical regulator of lipid metabolism and explains how mutations in this gene lead to severe hypertriglyceridemia. LMF1 is an endoplasmic reticulum (ER)–localized chaperone protein required for the post‑translational activation of three key vascular lipases: lipoprotein lipase (LPL), hepatic lipase (HL), and endothelial lipase (EL). These enzymes are essential for hydrolyzing triglycerides in circulating lipoproteins and enabling normal lipid clearance from the bloodstream.

Genetic studies in both mice and humans demonstrate that loss‑of‑function mutations in LMF1 result in combined lipase deficiency, characterized by markedly reduced activity of LPL and HL despite normal gene expression and protein production. This defect arises because LMF1 is specifically required for the maturation of homodimeric lipases, suggesting it facilitates the assembly or stabilization of inactive lipase subunits into fully functional enzyme dimers. Monomeric lipases do not depend on LMF1, highlighting its selective and specialized role.