LRCOL1

Leucine-rich colipase-like protein 1 is a small secreted protein (159 AA) containing colipase-like domains that functions as a cofactor/activator for lipid-degrading enzymes. The protein contains a signal peptide, 18 conserved cysteines forming multiple disulfide bonds, and two internal colipase-like domains similar to pancreatic colipase. Unlike pancreatic colipase which is produced by the pancreas, LRCOL1 is expressed in digestive tissues (small intestine, colon), liver, lymphatic endothelium, and is highly enriched in the epididymis (~50-fold). LRCOL1 is predicted to bind lipases and stabilize their activity at lipid-water interfaces, facilitating triglyceride hydrolysis in extracellular fluids. Expression in the male reproductive tract suggests a potential role in sperm maturation through lipid remodeling. The protein is secreted into extracellular spaces (intestinal lumen, lymph, seminal fluid) where it acts on lipid substrates. Direct biochemical studies and identification of specific lipase partners are still lacking.