RGD Reference Report - Molecular and functional characterization of a family of rat brain T-type calcium channels. - Rat Genome Database

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Molecular and functional characterization of a family of rat brain T-type calcium channels.

Authors: McRory, JE  Santi, CM  Hamming, KS  Mezeyova, J  Sutton, KG  Baillie, DL  Stea, A  Snutch, TP 
Citation: McRory JE, etal., J Biol Chem 2001 Feb 9;276(6):3999-4011.
RGD ID: 68748
Pubmed: PMID:11073957   (View Abstract at PubMed)
DOI: DOI:10.1074/jbc.M008215200   (Journal Full-text)

Voltage-gated calcium channels represent a heterogenous family of calcium-selective channels that can be distinguished by their molecular, electrophysiological, and pharmacological characteristics. We report here the molecular cloning and functional expression of three members of the low voltage-activated calcium channel family from rat brain (alpha(1G), alpha(1H), and alpha(1I)). Northern blot and reverse transcriptase-polymerase chain reaction analyses show alpha(1G), alpha(1H), and alpha(1I) to be expressed throughout the newborn and juvenile rat brain. In contrast, while alpha(1G) and alpha(1H) mRNA are expressed in all regions in adult rat brain, alpha(1I) mRNA expression is restricted to the striatum. Expression of alpha(1G), alpha(1H), and alpha(1I) subunits in HEK293 cells resulted in calcium currents with typical T-type channel characteristics: low voltage activation, negative steady-state inactivation, strongly voltage-dependent activation and inactivation, and slow deactivation. In addition, the direct electrophysiological comparison of alpha(1G), alpha(1H), and alpha(1I) under identical recording conditions also identified unique characteristics including activation and inactivation kinetics and permeability to divalent cations. Simulation of alpha(1G), alpha(1H), and alpha(1I) T-type channels in a thalamic neuron model cell produced unique firing patterns (burst versus tonic) typical of different brain nuclei and suggests that the three channel types make distinct contributions to neuronal physiology.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
calcium ion transport  IDA 68748 RGD 

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
low voltage-gated calcium channel activity  IDA 68748 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Cacna1h  (calcium voltage-gated channel subunit alpha1 H)

Objects referenced in this article
Gene CACNA1G calcium voltage-gated channel subunit alpha1 G Homo sapiens
Gene Cacna1g calcium voltage-gated channel subunit alpha1 G Rattus norvegicus
Gene Cacna1i calcium voltage-gated channel subunit alpha1 I Rattus norvegicus

Additional Information