Cav3.3

Description: calcium channel, voltage-dependent, T type, alpha 1I subunit
Gene: Cacna1i Synonyms: cacna1i, cav3.3, ca3.3, Ca(v)3.3

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Introduction

CACNA1I (also known as Cav3.3; KIAA1120) encodes Cav3.3, a T type LVA calcium channel found in neurons which is also know as a1I. Voltage-dependent calcium channels control the rapid entry of Ca(2+) into a variety of cell types and are therefore involved in both electrical and cellular signaling. T-type channels, such as CACNA1I, are activated by small membrane depolarizations and can generate burst firing and pacemaker activity

http://www.ncbi.nlm.nih.gov/gene/8911

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Gene

RGD ID	Chromosome	Position	Species
68944	7	118582279-118681537	Rat
1621299	15	80117668-80228722	Mouse
68996	22	39966758-40085740	Human

Cacna1i : calcium channel, voltage-dependent, T type, alpha 1I subunit

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Transcript

Acc No	Sequence	Length	Source
NM_020084	n/A	n/A	NCBI
NM_001044308	n/A	n/A	NCBI
NM_021096	n/A	n/A	NCBI
NM_001003406	n/A	n/A	NCBI

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Ontology

Accession	Name	Definition	Evidence
GO:0000786	nucleosome	A complex comprised of DNA wound around a multisubunit core and associated proteins, which forms the primary packing unit of DNA into higher order structures.	IEA
GO:0005634	nucleus	A membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. In most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing. In some species, or in specialized cell types, RNA metabolism or DNA replication may be absent.	IEA
GO:0016020	membrane	Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins.	IEA

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Interaction

Zinc

CaV 3.2 current (IC50 , 0.8 μM) is significantly more sensitive to Zn2 + than are CaV 3.1 and CaV 3.3 currents (IC50 , 80 μM and ∼160 μM, respectively). This inhibition of CaV 3 currents is associated with a shift to more negative membrane potentials of both steady-state inactivation for CaV 3.1, CaV 3.2 and CaV 3.3 and steady-state activation for CaV 3.1 and CaV 3.3 currents. We also document changes in kinetics, especially a significant slowing of the inactivation kinetics for CaV 3.1 and CaV 3.3, but not for CaV 3.2 currents. (Traboulsie [103])

Phorbol-12-myristate-13-acetate (PMA)

PMA augmented the current amplitudes of the three T-type channel isoforms (Cav3.1, Cav3.2, Cav3.3), but the fold stimulations and time courses differed. (Park [112])

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Protein

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Structure

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Distribution

T-type Ca2+ currents are central determinants of neuronal excitability that are present in the somatodendritic compartment of many types of neurones (Carbone & Lux, 1984 [1238]; Talley et al. 1999 [1242]).

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Expression

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Functional

Genetic and pharmacological inhibition of T-type Ca2+ currents has demonstrated the importance of these currents in various sensory systems, ranging from pain perception and hyperalgesia (Kim et al. 2003 [1243]; Ikeda et al. 2003 [1244]), mechanoreceptor function (Shin et al. 2003 [1245]) and to olfaction (Kawai & Miyachi, 2001 [1246]).

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Kinetics

T-type channels are distinguished from high voltage-activated (HVA)1 Ca2+ channels by their unique biophysical properties, including low voltage activation, fast activation and inactivation kinetics that produce a criss-crossing pattern between successive traces of a current-voltage (IV) protocol, slow deactivation kinetics, and tiny single channel conductance (Perez-Reyes [528], Armstrong [1237], Carbone [1238], Randall [340]).

Expression studies found that Cav3.3 channels generate currents with much slower activation and inactivation kinetics than Cav3.1 and Cav3.2 channels, which show the more typical transient kinetics described for native T-type channels (Perez-Reyes [528], Perez-Reyes [1239], Cribbs [1240], Lee [1241]).

Cav3.1 and Cav3.2 channels are activating and inactivating much faster than Cav3.3 channels. (Park [113])

The kinetics of T-type channels resemble those of Na+ channels, albeit on a slower time scale, suggesting that they may also inactivate by a ball-and-chain mechanism. However, preliminary evidence indicates that T-type channels inactivate by similar processes as HVA Ca2+ channels.Multiple structural elements contribute to the slow kinetics of Cav3.3 channels. (Park [113])

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Model

Model Cav3.3 (ID=42) Edit

Animal	CH
CellType	CHO
Age	0 Days
Temperature	0.0°C
Reversal	30.0 mV
Ion	Ca +
Ligand ion
Reference	Achraf Traboulsie et. al; J. Physiol. (Lond.) 2007 Jan 1
mpower	1.0
m Inf	1/(1+exp((v- -45.454426)/-5.073015))
m Tau	3.394938 +( 54.187616 / (1 + exp((v - -40.040397)/4.110392)))
hpower	1.0
h Inf	1 /(1+exp((v-(-74.031965))/8.416382))
h Tau	109.701136 + (0.003816 * exp(-v/4.781719))

MOD - xml - channelML

References

103

Traboulsie A et al. Subunit-specific modulation of T-type calcium channels by zinc.
J. Physiol. (Lond.), 2007 Jan 1 , 578 (159-71).

112

Park JY et al. Activation of protein kinase C augments T-type Ca2+ channel activity without changing channel surface density.
J. Physiol. (Lond.), 2006 Dec 1 , 577 (513-23).

113

Park JY et al. Multiple structural elements contribute to the slow kinetics of the Cav3.3 T-type channel.
J. Biol. Chem., 2004 May 21 , 279 (21707-13).

114

T-type Ca2+ channels encode prior neuronal activity as modulated recovery rates.
J. Physiol. (Lond.), 2006 Mar 15 , 571 (519-36).

115

Cataldi M et al. Zn(2+) slows down Ca(V)3.3 gating kinetics: implications for thalamocortical activity.
J. Neurophysiol., 2007 Oct , 98 (2274-84).

292

Kovacs K et al. Subcellular distribution of low-voltage activated T-type Ca2+ channel subunits (Ca(v)3.1 and Ca(v)3.3) in reticular thalamic neurons of the cat.
J. Neurosci. Res., 2010 Feb 1 , 88 (448-60).

528

Perez-Reyes E Molecular physiology of low-voltage-activated t-type calcium channels.
Physiol. Rev., 2003 Jan , 83 (117-61).

1237

Armstrong CM et al. Two distinct populations of calcium channels in a clonal line of pituitary cells.
Science, 1985 Jan 4 , 227 (65-7).

1238

Carbone E et al. A low voltage-activated, fully inactivating Ca channel in vertebrate sensory neurones.
Nature, 1984 Aug 9-15 , 310 (501-2).

340

Randall AD et al. Contrasting biophysical and pharmacological properties of T-type and R-type calcium channels.
Neuropharmacology, 1997 Jul , 36 (879-93).

1239

Perez-Reyes E et al. Molecular characterization of a neuronal low-voltage-activated T-type calcium channel.
Nature, 1998 Feb 26 , 391 (896-900).

1240

Cribbs LL et al. Cloning and characterization of alpha1H from human heart, a member of the T-type Ca2+ channel gene family.
Circ. Res., 1998 Jul 13 , 83 (103-9).

1241

Lee JH et al. Cloning and expression of a novel member of the low voltage-activated T-type calcium channel family.
J. Neurosci., 1999 Mar 15 , 19 (1912-21).

1242

Talley EM et al. Differential distribution of three members of a gene family encoding low voltage-activated (T-type) calcium channels.
J. Neurosci., 1999 Mar 15 , 19 (1895-911).

1243

Kim D et al. Thalamic control of visceral nociception mediated by T-type Ca2+ channels.
Science, 2003 Oct 3 , 302 (117-9).

1244

Ikeda H et al. Synaptic plasticity in spinal lamina I projection neurons that mediate hyperalgesia.
Science, 2003 Feb 21 , 299 (1237-40).

1245

Shin JB et al. A T-type calcium channel required for normal function of a mammalian mechanoreceptor.
Nat. Neurosci., 2003 Jul , 6 (724-30).

1246

Kawai F et al. Enhancement by T-type Ca2+ currents of odor sensitivity in olfactory receptor cells.
J. Neurosci., 2001 May 15 , 21 (RC144).

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Credits

Contributors: Rajnish Ranjan, Michael Schartner

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/ionchannels/87/ , accessed on [date]