Agonist-induced endocytosis of lysophosphatidic acid-coupled LPA1/EDG-2 receptors via a dynamin2- and Rab5-dependent pathway

Academic Article

Abstract

  • Lysophosphatidic acid (LPA) is a serum-borne phospholipid that exerts a pleiotropic range of effects on cells through activation of three closely related G-protein-coupled receptors termed LPA1/EDG-2,LPA2/EDG-4 and LPA3/EDG-7. Of these receptors, the LPA1 receptor is the most widely expressed. In this study, we investigated the agonist-induced endocytosis of the human LPA1receptor, bearing an N-terminal FLAG epitope tag, in stably transfected HeLa cells. Treatment with LPA induced the rapid endocytosis of approximately 40%of surface LPA1 within 15 minutes. Internalization was both dose dependent and LPA specific since neither lysophophatidylcholine nor sphingosine-1-phosphate induced LPA1 endocytosis. Removal of agonist following 30 minutes incubation resulted in recycling of LPA1 back to the cell surface. LPA1 internalization was strongly inhibited by dominant-inhibitory mutants of both dynamin2 (K44A) and Rab5a (S34N). In addition, both dynamin2 K44A and Rab5 S34N mildly inhibited LPA1-dependent activation of serum response factor. Finally, our results also indicate that LPA1 exhibits basal, LPA-dependent internalization in the presence of serum-containing medium.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Murph MM; Scaccia LA; Volpicelli LA; Radhakrishna H
  • Start Page

  • 1969
  • End Page

  • 1980
  • Volume

  • 116
  • Issue

  • 10