Dual regulation of sphingosine 1-phosphate-induced phospholipase D activity through RhoA and protein kinase C-alpha in C2C12 myoblasts.
Previous studies showed that in C2C12 cells, phospholipase D (PLD) and its known regulators, RhoA and protein kinase Calpha (PKCalpha), were downstream effectors in sphingosine 1-phosphate (SPP) signalling. Moreover, the role of PKC for SPP-mediated PLD activation and the requirement of PKCalpha for RhoA translocation were reported. The present results demonstrated that inactivation of RhoA, by overexpression of RhoGDP dissociation inhibitor (RhoGDI) as well as treatment with C3 exotoxin, attenuated SPP-stimulated PLD activity, supporting the involvement of RhoA in the stimulation of PLD activity by the bioactive lipid in C2C12 myoblasts. In addition, the effect of PKCalpha inhibitor Gö6976 on the SPP-induced PLD activation in myoblasts, where RhoA function was inactivated, was consistent with a dual regulation of the enzyme through RhoA and PKCalpha. Interestingly, the subcellular distribution of PLD isoforms, RhoA and PKCalpha, in SPP-stimulated cells supported the view that the functional relationship between the two PLD regulators, demonstrated to occur in SPP signalling, represents a novel mechanism of regulation of specifically localized PLD.
Meacci
E
E
Dipartimento di Scienze Biochimiche, Universitá di Firenze, Viale G.B. Morgagni 50, 50134, Firenze, Italy.
Donati
C
C
Cencetti
F
F
Oka
T
T
Komuro
I
I
Farnararo
M
M
Bruni
P
P
D036002:ADP Ribose Transferases / Q000494:pharmacology; D000818:Animals; D001905:Botulinum Toxins; D002227:Carbazoles / Q000494:pharmacology; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000502:physiology*; D008246:Lysophospholipids; D018482:Muscle, Skeletal / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000502:physiology*; D051571:Protein Kinase C-alpha; D021381:Protein Transport; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D014162:Transfection; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020742:rhoA GTP-Binding Protein / Q000502:physiology*
D002227:Carbazoles; D004791:Enzyme Inhibitors; D020730:Guanine Nucleotide Dissociation Inhibitors; D007211:Indoles; D007527:Isoenzymes; D008246:Lysophospholipids; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; C081021:Go 6976; C060506:sphingosine 1-phosphate; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D010739:Phospholipase D; D001905:Botulinum Toxins; D020742:rhoA GTP-Binding Protein; D013110:Sphingosine