Identification of three subunits of the high affinity omega-conotoxin MVIIC-sensitive Ca2+ channel.
N-, P- and Q-type voltage-dependent Ca2+ channels control neurotransmitter release in the nervous system and are blocked by omega-conotoxin MVIIC. In this study, both a high affinity and a low affinity binding site for omega-conotoxin MVIIC were detected in rabbit brain. The low affinity binding site is shown to be present on the N-type Ca2+ channel. Using optimized conditions for specific labeling of the high affinity omega-conotoxin MVIIC receptor and a panel of subunit specific antibodies, the molecular structure of the high affinity receptor was investigated. We demonstrate for the first time that this receptor is composed of at least alpha1A, alpha2delta, and any one of the four brain beta subunits. Such association of different beta subunits with alpha1A and alpha2delta components may produce Ca2+ channels with distinct functional properties, such as P- and Q-type.
Liu
H
H
Howard Hughes Medical Institute, Department of Physiology and Biophysics, Program in Neuroscience, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
De Waard
M
M
Scott
V E
VE
Gurnett
C A
CA
Lennon
V A
VA
Campbell
K P
KP
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000378:metabolism / Q000494:pharmacology*; D015220:Calcium Channels / Q000737:chemistry* / Q000187:drug effects* / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D066298:In Vitro Techniques; D007700:Kinetics; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D011487:Protein Conformation; D011817:Rabbits; D051381:Rats; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D017931:DNA Primers; D010455:Peptides; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC