Hormone-sensitive lipase

Hormone-sensitive lipase is a protein found in the cytosol and on the lipid droplet of adipocytes.

Function
It functions to hydrolyze triacylglycerols from the lipid droplet, freeing fatty acids and glycerols.

It is active when the body needs to mobilise energy stores, and so responds positively to glucagon and negatively to insulin.

Activation
It may be activated by two mechanisms.


 * In the first, it is phosphorylated by perilipin A, causing it to move to the surface of the lipid droplet, where it may begin hydrolyzing the lipid droplet.


 * Alternately, it may be activated by a cAMP-dependent protein kinase. This pathway is significantly less effective than the first, which is necessary to lipid mobilization in response to cyclic AMP, which itself is provided by beta adrenergic stimulation or the glucagon receptor.