title: Physical and functional interactions of the lysophosphatidic acid receptors with PDZ domain-containing Rho guanine nucleotide exchange factors (RhoGEFs).
abstract: Lysophosphatidic acid (LPA) is a serum-derived phospholipid that induces a variety of biological responses in various cells via heterotrimeric G protein-coupled receptors (GPCRs) including LPA1, LPA2, and LPA3. LPA-induced cytoskeletal changes are mediated by Rho family small GTPases, such as RhoA, Rac1, and Cdc42. One of these small GTPases, RhoA, may be activated via Galpha(12/13)-linked Rho-specific guanine nucleotide exchange factors (RhoGEFs) under LPA stimulation although the detailed mechanisms are poorly understood. Here, we show that the C terminus of LPA1 and LPA2 but not LPA3 interact with the PDZ domains of PDZ domain-containing RhoGEFs, PDZ-RhoGEF, and LARG, which are comprised of PDZ, RGS, Dbl homology (DH), and pleckstrin homology (PH) domains. In LPA1- and LPA2-transfected HEK293 cells, LPA-induced RhoA activation was observed although the C terminus of LPA1 and LPA2 mutants, which failed to interact with the PDZ domains, did not cause LPA-induced RhoA activation. Furthermore, overexpression of the PDZ domains of PDZ domain-containing RhoGEFs served as dominant negative mutants for LPA-induced RhoA activation. Taken together, these results indicate that formation of the LPA receptor/PDZ domain-containing RhoGEF complex plays a pivotal role in LPA-induced RhoA activation.
authors.affiliation: School of Allied Health Sciences, Faculty of Medicine, Osaka University, Yamadaoka, Suita-shi, Osaka 565-0871, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohoka
authors.forename: Mikihiko
authors.initials: M
authors.lastname: Kogo
authors.forename: Shinobu
authors.initials: S
authors.lastname: Inagaki
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D004789:Enzyme Activation; D005799:Genes, Dominant; D005822:Genetic Vectors; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D020935:MAP Kinase Signaling System; D051379:Mice; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D049368:Receptors, Lysophosphatidic Acid / Q000737:chemistry*; D064067:Rho Guanine Nucleotide Exchange Factors; D015398:Signal Transduction; D014162:Transfection
chemical_list: C577222:ARHGEF12 protein, human; C577223:Arhgef12 protein, mouse; D017931:DNA Primers; D020662:Guanine Nucleotide Exchange Factors; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D064067:Rho Guanine Nucleotide Exchange Factors