LIPE

LIPE is the gene symbol for lipase E, hepatic-type, a member of the lipase enzyme family in humans. The official gene symbol LIPE is used in human genome nomenclature to designate this enzyme, which is commonly referred to as hormone-sensitive lipase (HSL) in physiological contexts. The LIPE-encoded enzyme plays a central role in lipid mobilization.

The enzyme catalyzes the hydrolysis of triacylglycerols stored in adipose tissue, converting triglycerides to diacylglycerols and free fatty acids, with activity also observed in liver, muscle, and other tissues. This lipolytic process provides fatty acids for energy production and metabolic signaling. LIPE acts within cellular lipid droplets and is part of a broader lipase family that participates in lipid metabolism across multiple tissues.

Regulation of LIPE activity is tightly controlled by hormonal and nutritional cues. In response to catecholamines, cyclic AMP–dependent protein kinase A (PKA) phosphorylates LIPE, activating lipolysis. Insulin signaling counteracts this pathway, reducing LIPE activity and thereby lowering lipolysis. Post-translational modifications and tissue-specific factors influence LIPE activity and its contribution to whole-body lipid homeostasis.

Expression and clinical relevance: LIPE is abundantly expressed in adipose tissue and is present at lower levels in liver and other organs. Genetic variation and expression differences in LIPE have been investigated for associations with plasma lipid levels, obesity, and insulin resistance, though findings are variable and influenced by context such as diet and sex.

Research and models: In animal studies, altered LIPE expression affects lipolysis and fat mass, providing insight into energy balance and metabolic regulation. LIPE remains a focus in studies of metabolic syndrome and fat metabolism.

See also: hormone-sensitive lipase, lipase family, lipolysis, metabolic regulation.