title: Lysophosphatidic acid and thrombin receptors require both G alpha12 and G alpha13 to regulate axonal morphology in hippocampal neurons.
abstract: The G alpha subunits of the G(12) family of heterotrimeric guanine nucleotide-binding proteins (G proteins), defined by G alpha(12) and G alpha(13), have many cellular functions in common, including stimulation of stress fiber formation and focal adhesion assembly via the small GTPase RhoA activation. We and others previously showed that G alpha(12) and G alpha(13) mediate neurite retraction in neuronal cell lines, but their roles in primary cultured neurons have not been adequately understood. Here, we found that expression of constitutively active mutants of G alpha(12) or G alpha(13) caused growth cone collapse dependent on Rho-kinase activity in hippocampal neurons. The stimulation of thrombin and lysophosphatidic acid (LPA) receptors, which have been thought to selectively couple to G alpha(12) and G alpha(13), respectively, caused growth cone collapse and suppressed axon branching dependent on Rho-kinase activity in hippocampal neurons. Thrombin- and LPA-induced growth cone collapse was suppressed by both single knockdown of G alpha(12) and G alpha(13) with short hairpin RNAs and this suppression was augmented by double knockdown of both G alpha(12) and G alpha(13). These results suggest that thrombin and LPA receptors couple to both G alpha(12) and G alpha(13) for growth cone collapse.
authors.affiliation: Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Yamazaki
authors.forename: Hironori
authors.initials: H
authors.lastname: Katoh
authors.forename: Manabu
authors.initials: M
authors.lastname: Negishi
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism / Q000502:physiology; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure; D015153:Blotting, Western; D002478:Cells, Cultured; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D005260:Female; D044365:GTP-Binding Protein alpha Subunits, G12-G13 / Q000378:metabolism*; D006624:Hippocampus / Q000502:physiology* / Q000648:ultrastructure; D007202:Indicators and Reagents; D008246:Lysophospholipids / Q000502:physiology*; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000502:physiology* / Q000648:ultrastructure; D010957:Plasmids / Q000235:genetics / Q000502:physiology; D011247:Pregnancy; D012313:RNA / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D018179:Receptors, Thrombin / Q000502:physiology*; D039961:Semaphorins / Q000378:metabolism / Q000502:physiology; D014162:Transfection
chemical_list: D015703:Antigens, CD; C093224:CD100 antigen; D007202:Indicators and Reagents; D008246:Lysophospholipids; D018179:Receptors, Thrombin; D039961:Semaphorins; D012313:RNA; D044365:GTP-Binding Protein alpha Subunits, G12-G13; C032881:lysophosphatidic acid