Type-1 cannabinoid receptors colocalize with caveolin-1 in neuronal cells.
Type-1 (CB1) and type-2 (CB2) cannabinoid receptors belong to the rhodopsin family of G protein-coupled receptors, and are activated by endogenous lipids termed "endocannabinoids". Recent reports have demonstrated that CB1R, unlike CB2R and other receptors and metabolic enzymes of endocannabinoids, functions in the context of lipid rafts, i.e. plasma membrane microdomains which may be important in modulating signal transduction. Here, we present novel data based on cell subfractionation, immunoprecipitation and confocal microscopy studies, that show that in C6 cells CB1R co-localizes almost entirely with caveolin-1. We also show that trafficking of CB1R in response to the raft disruptor methyl-beta-cyclodextrin (MCD) is superimposable on that of caveolin-1, and that MCD treatment increases the accessibility of CB1R to its specific antibodies. These findings may be relevant for the manifold CB1R-dependent activities of endocannabinoids, like the regulation of apoptosis and of neurodegenerative diseases.
Bari
Monica
M
Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, 00133 Rome, Italy.
Oddi
Sergio
S
De Simone
Chiara
C
Spagnolo
Paola
P
Gasperi
Valeria
V
Battista
Natalia
N
Centonze
Diego
D
Maccarrone
Mauro
M
D000818:Animals; D051242:Caveolin 1 / Q000378:metabolism*; D002458:Cell Fractionation / Q000379:methods; D045744:Cell Line, Tumor; D005910:Glioma / Q000473:pathology; D047468:Immunoprecipitation / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D043884:Receptor, Cannabinoid, CB1 / Q000378:metabolism*; D013997:Time Factors; D047392:beta-Cyclodextrins / Q000494:pharmacology
C495537:Cav1 protein, rat; D051242:Caveolin 1; D043884:Receptor, Cannabinoid, CB1; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin
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