The alpha(2)delta subunit augments functional expression and modifies the pharmacology of Ca(V)1.3 L-type channels.
The auxiliary Ca(V)alpha(2)delta-1 subunit is an important component of voltage-gated Ca(2+) (Ca(V)) channel complexes in many tissues and of great interest as a drug target. Nevertheless, its exact role in specific cell functions is still unknown. This is particularly important in the case of the neuronal L-type Ca(V) channels where these proteins play a key role in the secretion of neurotransmitters and hormones, gene expression, and the activation of other ion channels. Therefore, using a combined approach of patch-clamp recordings and molecular biology, we studied the role of the Ca(V)alpha(2)delta-1 subunit on the functional expression and the pharmacology of recombinant L-type Ca(V)1.3 channels in HEK-293 cells. Co-expression of Ca(V)alpha(2)delta-1 significantly increased macroscopic currents and conferred the Ca(V)1.3alpha(1)/Ca(V)beta(3) channels sensitivity to the antiepileptic/analgesic drugs gabapentin and AdGABA. In contrast, Ca(V)alpha(2)delta-1 subunits harboring point mutations in N-glycosylation consensus sequences or the proteolytic site as well as in conserved cysteines in the transmembrane delta domain of the protein, reduced functionality in terms of enhancement of Ca(V)1.3alpha(1)/Ca(V)beta(3) currents. In addition, co-expression of the delta domain drastically inhibited macroscopic currents through recombinant Ca(V)1.3 channels possibly by affecting channel synthesis. Together these results provide several lines of evidence that the Ca(V)alpha(2)delta-1 auxiliary subunit may interact with Ca(V)1.3 channels and regulate their functional expression.
Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav-IPN, Mexico City, Mexico.
Arturo
A
Andrade
Alejandro
A
Sandoval
Ricardo
R
González-Ramírez
Diane
D
Lipscombe
Kevin P
KP
Campbell
Ricardo
R
Felix
D000085:Acetates / Q000494:pharmacology; D000588:Amines / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology; D000077206:Gabapentin; D006801:Humans; D018408:Patch-Clamp Techniques; D011817:Rabbits; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives / Q000494:pharmacology
C503772:2-aminomethyl-2-tricyclo(3.3.1.1(1,7))decaneacetic acid hydrochloride; D000085:Acetates; D000588:Amines; C486060:Cacna2d1 protein, rat; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D003509:Cyclohexanecarboxylic Acids; D011993:Recombinant Fusion Proteins; C093712:Cacna1d protein, rat; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D002118:Calcium