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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1995-4-27
|
| pubmed:abstractText |
Several types of structurally homologous high voltage-gated Ca2+ channels (L-, P- and N-type) have been identified via biochemical, pharmacological and electrophysiological techniques. Among these channels, the cardiac L-type and the brain BI-2 Ca2+ channel display significantly different biophysical properties. The BI-2 channel exhibits more rapid voltage-dependent current activation and inactivation and smaller single-channel conductance compared to the L-type Ca2+ channel. To examine the molecular basis for the functional differences between the two structurally related Ca2+ channels, we measured macroscopic and single-channel currents from oocytes injected with wild-type and various chimeric channel alpha 1 subunit cRNAs. The results show that a chimeric channel in which the segment between S5-SS2 in repeat IV of the cardiac L-type Ca2+ channel, was replaced by the corresponding region of the BI-2 channel, exhibited macroscopic current activation and inactivation time-courses and single-channel conductance, characteristic of the BI-2 Ca2+ channel. The voltage-dependence of steady-state inactivation was not affected by the replacement. Chimeras, in which the SS2-S6 segment in repeat III or IV of the cardiac channel was replaced by the corresponding BI-2 sequence, exhibited altered macroscopic current kinetics without changes in single-channel conductance. These results suggest that part of the S5-SS2 segment plays a critical role in determining voltage-dependent current activation and inactivation and single-channel conductance and that the SS2-S6 segment may control voltage-dependent kinetics of the Ca2+ channel.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Nov
|
| pubmed:issn |
0300-8177
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
23
|
| pubmed:volume |
140
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
93-102
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:7898492-Amino Acid Sequence,
pubmed-meshheading:7898492-Animals,
pubmed-meshheading:7898492-Base Sequence,
pubmed-meshheading:7898492-Brain,
pubmed-meshheading:7898492-Calcium Channels,
pubmed-meshheading:7898492-Female,
pubmed-meshheading:7898492-Heart,
pubmed-meshheading:7898492-Ion Channel Gating,
pubmed-meshheading:7898492-Macromolecular Substances,
pubmed-meshheading:7898492-Membrane Potentials,
pubmed-meshheading:7898492-Molecular Sequence Data,
pubmed-meshheading:7898492-Mutagenesis, Site-Directed,
pubmed-meshheading:7898492-Oocytes,
pubmed-meshheading:7898492-Polymerase Chain Reaction,
pubmed-meshheading:7898492-Protein Structure, Secondary,
pubmed-meshheading:7898492-RNA, Complementary,
pubmed-meshheading:7898492-Rabbits,
pubmed-meshheading:7898492-Recombinant Fusion Proteins
|
| pubmed:year |
1994
|
| pubmed:articleTitle |
Alteration of channel characteristics by exchange of pore-forming regions between two structurally related Ca2+ channels.
|
| pubmed:affiliation |
Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Ohio 45267-0575.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
|