Galpha(q)-mediated plasma membrane translocation of sphingosine kinase-1 and cross-activation of S1P receptors.
Sphingosine-1-phosphate (S1P), formed by sphingosine kinases (SphKs), regulates cellular proliferation and migration by acting as an agonist at specific receptors or intracellularly. Since S1P's effects are probably dependent on subcellular localization of its formation and degradation, we have studied the influence of G protein-coupled receptors on the localization of SphK1. Activation of Gq-coupled receptors induced a profound, rapid (half-life 3-5 s) and long-lasting (> 2 h) translocation of SphK1 to the plasma membrane. This was mimicked by expression of constitutively active G protein alpha-subunits specifically of the Gq family. Classical Gq signalling pathways, or phosphorylation at Ser225, phospholipase D and Ca2+/calmodulin were not involved in M3 receptor-induced SphK1 translocation in HEK-293 cells. Translocation was associated with S1P receptor internalization, which was dependent on catalytic activity of SphK1 and S1P receptor binding and thus resulted from S1P receptor cross-activation. It is concluded that SphK1 is an important effector of Gq-coupled receptors, linking them via cross-activation of S1P receptors to G(i) and G12/13 signalling pathways.
ter Braak
Michael
M
Institut für Pharmakologie, Universitätsklinikum Essen, Essen, Germany.
Danneberg
Kerstin
K
Lichte
Karin
K
Liphardt
Kerstin
K
Ktistakis
Nicholas T
NT
Pitson
Stuart M
SM
Hla
Timothy
T
Jakobs
Karl H
KH
Meyer zu Heringdorf
Dagmar
D
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D004075:Diglycerides / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism*; D006801:Humans; D051379:Mice; D010739:Phospholipase D / Q000378:metabolism; D010768:Phosphoserine / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D043587:Receptor, Muscarinic M3 / Q000378:metabolism; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000099157:Sphingosine Kinase
D004075:Diglycerides; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D010739:Phospholipase D; D010768:Phosphoserine; D017853:Phosphotransferases (Alcohol Group Acceptor); D011493:Protein Kinase C; D043587:Receptor, Muscarinic M3; D049349:Receptors, Lysosphingolipid; D013110:Sphingosine; D000099157:Sphingosine Kinase; C061800:N,N-dimethylsphingosine