Measurement of autotaxin/lysophospholipase D activity.

Lysophosphatidic acid (LPA) is a bioactive lipid mediator present in the blood and other biological fluids at physiologically relevant concentrations. In the cardiovascular system, studies using in vitro and in vivo experimental models indicate that LPA stimulates platelet activation, differentiation and migration of vascular smooth muscle cells, and changes in vascular tone. A growing body of evidence suggests that aberrant production and actions of LPA could play an important role in atherothrombotic disease. Hydrolysis of lysophospholipids by the secreted plasma protein autotaxin/lysophospholipase D (lysoPLD) is a major mechanism for generation of LPA in the blood. This chapter describes methods for determining the activity of recombinant autotaxin/lysoPLD using radiolabeled and fluorogenic substrates.