Molecular cloning of a high-affinity receptor for the growth factor-like lipid mediator lysophosphatidic acid from Xenopus oocytes.
Lysophosphatidic acid (1-acyl-2-lyso-snglycero-3-phosphate, LPA) is a multifunctional lipid mediator found in a variety of organisms that span the phylogenetic tree from humans to plants. Although its physiological function is not clearly understood, LPA is a potent regulator of mammalian cell proliferation; it is one of the major mitogens found in blood serum. In Xenopus laevis oocytes, LPA elicits oscillatory Cl- currents. This current, like other effects of LPA, is consistent with a plasma membrane receptor-mediated activation of G protein-linked signal transduction pathways. Herein we report the identification of a complementary DNA from Xenopus that encodes a functional high-affinity LPA receptor. The predicted structure of this protein of 372 amino acids contains features common to members of the seven transmembrane receptor superfamily with a predicted extracellular amino and intracellular carboxyl terminus. An antisense oligonucleotide derived from the first 5-11 predicted amino acids, selectively inhibited the expression of the endogenous high-affinity LPA receptors in Xenopus oocytes, whereas the same oligonucleotide did not affect the low-affinity LPA receptor. Expression of the full-length cRNA in oocytes led to an increase in maximal Cl- current due to increased expression of the high-affinity LPA receptor, but activation of the low-affinity receptor was, again, unaffected. Oocytes expressing cRNA prepared from this clone showed no response to other lipid mediators including prostaglandins, leukotrienes, sphingosine 1-phosphate, sphingosylphosphorylcholine, and platelet-activating factor, suggesting that the receptor is highly selective for LPA.
Guo
Z
Z
Department of Physiology and Biophysics, University of Tennessee, Memphis 38163, USA.
Liliom
K
K
Fischer
D J
DJ
Bathurst
I C
IC
Tomei
L D
LD
Kiefer
M C
MC
Tigyi
G
G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D008246:Lysophospholipids / Q000378:metabolism*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism*; D018075:RNA, Complementary / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D014982:Xenopus laevis
D008246:Lysophospholipids; D018075:RNA, Complementary; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid