Lysophosphatidic acid produced by Autotaxin acts as an allosteric modulator of its catalytic efficiency

Autotaxin is a secreted phosphodiesterase that converts lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA). LPA controls key cellular responses such as migration, proliferation and survival, implicating ATX-LPA signalling in various (patho)physiological processes and establishing it as a drug target. ATX structural and functional studies have revealed an orthosteric and an allosteric site, the \"pocket\" and the \"tunnel\". Here, we revisit the kinetics of the ATX catalytic cycle in light of allosteric regulation, dissecting the different steps and pathways that lead to LPC hydrolysis. Consolidating all experimental kinetics data to a comprehensive catalytic model supported by molecular modelling simulations, suggests a positive feedback mechanism, regulated by the abundance of the LPA products activating hydrolysis of different LPC species. Our results complement and extend current understanding of ATX hydrolysis in light of the allosteric regulation by produced LPA species, and have implications for the design and application of orthosteric and allosteric ATX inhibitors.