Edg-2/Vzg-1 couples to the yeast pheromone response pathway selectively in response to lysophosphatidic acid.
We have functionally expressed the human cDNA encoding the putative lysophosphatidic acid (LPA) receptor Edg-2 (Vzg-1) in Saccharomyces cerevisiae in an attempt to determine the agonist specificity of this G-protein-coupled receptor. LPA activated the pheromone response pathway in S. cerevisiae expressing Edg-2 in a time- and dose-dependent manner as determined by induction of a pheromone-responsive FUS1::lacZ reporter gene. LPA-mediated activation of the pheromone response pathway was dependent on mutational inactivation of the SST2 gene, the GTPase-activating protein for the yeast G alpha protein (the GPA1 gene product). This indicates that, in sst2 delta yeast cells, Edg-2 can efficiently couple to the yeast heterotrimeric G-protein in response to LPA and activate the yeast mitogen-activated protein kinase pathway. The Edg-2 receptor showed a high degree of specificity for LPA; other lyso-glycerophospholipids, sphingosine 1-phosphate, and diacyl-glycerophospholipids did not activate FUS1::lacZ. LPA analogs including a cyclic phosphoester form and ether-linked forms of LPA activated FUS1::lacZ, although fatty acid chains of 6 and 10 carbons did not activate FUS1::lacZ, suggesting a role for the side chain in ligand binding or receptor activation. These results indicate that Edg-2 encodes a highly specific LPA receptor.
Erickson
J R
JR
LXR Biotechnology Inc., Richmond, California 94804, USA. jerickson@lxr.com
Wu
J J
JJ
Goddard
J G
JG
Tigyi
G
G
Kawanishi
K
K
Tomei
L D
LD
Kiefer
M C
MC
D004305:Dose-Response Relationship, Drug; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D008074:Lipoproteins / Q000378:metabolism*; D008246:Lysophospholipids / Q000494:pharmacology*; D010675:Pheromones / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors
D005656:Fungal Proteins; D008074:Lipoproteins; D008246:Lysophospholipids; C095063:MFA2 protein, S cerevisiae; D010675:Pheromones; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D029701:Saccharomyces cerevisiae Proteins; D019204:GTP-Binding Proteins