Coordinated action of NSF and PKC regulates GABAB receptor signaling efficacy.
The obligatory heterodimerization of the GABAB receptor (GBR) raises fundamental questions about molecular mechanisms controlling its signaling efficacy. Here, we show that NEM sensitive fusion (NSF) protein interacts directly with the GBR heterodimer both in rat brain synaptosomes and in CHO cells, forming a ternary complex that can be regulated by agonist stimulation. Inhibition of NSF binding with a peptide derived from GBR2 (TAT-Pep-27) did not affect basal signaling activity but almost completely abolished agonist-promoted GBR desensitization in both CHO cells and hippocampal slices. Taken with the role of PKC in the desensitization process, our observation that TAT-Pep-27 prevented both agonist-promoted recruitment of PKC and receptor phosphorylation suggests that NSF is a priming factor required for GBR desensitization. Given that GBR desensitization does not involve receptor internalization, the NSF/PKC coordinated action revealed herein suggests that NSF can regulate GPCR signalling efficacy independently of its role in membrane trafficking. The functional interaction between three bona fide regulators of neurotransmitter release, such as GBR, NSF and PKC, could shed new light on the modulation of presynaptic GBR action.
Pontier
Stéphanie M
SM
Département de Biochimie and Groupe de Recherche Universitaire sur le Médicament, Institut de recherche en immunologie et Cancérologie, Université de Montréal, Montréal, Qc, Canada.
Lahaie
Nicolas
N
Ginham
Rachel
R
St-Gelais
Fannie
F
Bonin
Hélène
H
Bell
David J
DJ
Flynn
Helen
H
Trudeau
Louis-Eric
LE
McIlhinney
Jeffrey
J
White
Julia H
JH
Bouvier
Michel
M
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D019281:Dimerization; D019204:GTP-Binding Proteins / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D052066:N-Ethylmaleimide-Sensitive Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009474:Neurons / Q000166:cytology; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D021122:Protein Subunits; D021381:Protein Transport; D051381:Rats; D018080:Receptors, GABA-B / Q000378:metabolism*; D015398:Signal Transduction; D013816:Thermodynamics
D010455:Peptides; D021122:Protein Subunits; D018080:Receptors, GABA-B; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D052066:N-Ethylmaleimide-Sensitive Proteins