Lysophosphatidic acid receptor 4 is a protein in humans that is encoded by LPAR4 gene. Receptor for lysophosphatidic acid (LPA), a mediator of diverse cellular activities. Transduces a signal by increasing the intracellular calcium ions and by stimulating adenylyl cyclase activity. The rank order of potency for agonists of this receptor is 1-oleoyl- > 1-stearoyl- > 1-palmitoyl- > 1-myristoyl- > 1-alkyl- > 1-alkenyl-LPA.