Receptor-activated phospholipase D is present in caveolin-3-enriched light membranes of C2C12 myotubes.
Caveolin-3 (cav-3) is a key structural component of caveolar membrane in skeletal muscle. Cav-3-enriched light membrane (CELM) fractions obtained from C2C12 myotubes contain phospholipase D1 (PLD1) and its major regulators, RhoA and protein kinase Calpha (PKCalpha). All these proteins were found bound to cav-3. An in vivo assay of PLD activity, which allows to localize the reaction product in CELMs, indicated that the enzyme associated to this membrane microdomain was active. Moreover, bradykinin (BK), thrombin and phorbol 12-myristate 13-acetate induced rapid stimulation of PLD activity in CELMs. The cav-3-PLD1 complex was not affected by BK treatment, whereas the agonist induced a marked increase of RhoA association with cav-3. Furthermore, BK-induced PLD activation in CELMs was dependent, at least in part, on PKCalpha.
Meacci
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Dipartimento di Scienze Biochimiche, Università di Firenze, Viale G. B. Morgagni 50, 50134, Firenze, Italy. biocell@scibio.unifi.it
Donati
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C
Cencetti
F
F
Romiti
E
E
Farnararo
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M
Bruni
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P
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D051244:Caveolin 3; D022461:Caveolins; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D004789:Enzyme Activation / Q000187:drug effects; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D008246:Lysophospholipids; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D051379:Mice; D008934:Mitogens / Q000494:pharmacology; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051571:Protein Kinase C-alpha; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
C495548:Cav3 protein, mouse; D051244:Caveolin 3; D022461:Caveolins; D007527:Isoenzymes; D008246:Lysophospholipids; D008565:Membrane Proteins; D008934:Mitogens; C060506:sphingosine 1-phosphate; C496630:Prkca protein, mouse; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D010739:Phospholipase D; C106801:phospholipase D1; D013917:Thrombin; D020742:rhoA GTP-Binding Protein; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin