Stimulation of Galphaq-coupled M1 muscarinic receptor causes reversible spectrin redistribution mediated by PLC, PKC and ROCK.
Spectrin is a cytoskeletal protein that plays a role in formation of the specialized plasma membrane domains. However, little is known of the molecular mechanism that regulates responses of spectrin to extracellular stimuli, such as activation of G-protein-coupled receptor (GPCR). We have found that alphaII spectrin is a component of the Galpha(q/11)-associated protein complex in CHO cells stably expressing the M1 muscarinic receptor, and investigated the effect of activation of GPCR on the cellular localization of yellow-fluorescent-protein-tagged alphaII spectrin. Stimulation of Galpha(q/11)-coupled M1 muscarinic receptor triggered reversible redistribution of alphaII spectrin following a rise in intracellular Ca2+ concentration. This redistribution, accompanied by non-apoptotic membrane blebbing, required an intact actin cytoskeleton and was dependent on activation of phospholipase C, protein kinase C, and Rho-associated kinase ROCK. Muscarinic-agonist-induced spectrin remodeling appeared particularly active at localized domains, which is clear contrast to that caused by constitutive activation of ROCK and to global rearrangement of the spectrin lattice caused by changes in osmotic pressure. These results suggest a role for spectrin in providing a dynamic and reversible signaling platform to the specific domains of the plasma membrane in response to stimulation of GPCR.
University of Leeds, Institute of Membrane and Systems Biology, Garstang Building, Mount Preston Street, Leeds LS2 9JT, UK. m.street@bmb.leeds.ac.uk
Miyoko
M
Street
Stephen J
SJ
Marsh
Paul R
PR
Stabach
Jon S
JS
Morrow
David A
DA
Brown
Noel J
NJ
Buckley
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology; D006224:Cricetinae; D003520:Cyclophosphamide; D004317:Doxorubicin; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D043643:Receptor, Muscarinic M1 / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism; D015398:Signal Transduction; D013049:Spectrin / Q000378:metabolism*; D010738:Type C Phospholipases / Q000502:physiology; D014750:Vincristine; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic; D013049:Spectrin; D014750:Vincristine; D004317:Doxorubicin; D003520:Cyclophosphamide; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010738:Type C Phospholipases; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D002118:Calcium