Cav2.2
Description: calcium channel, voltage-dependent, N type, alpha 1B subunit Gene: Cacna1b Synonyms: ca2.2, BIII, CACNN, Cav2.2, CACNL1A5, CACNA1B
The N-type calcium channels, also known as a1B or Cav2.2, are high voltage activated (HCA) calcium channels found presynaptically. For a longer introduction, see page 502 in the review [477]. See also the Channelpedia entry for Cav2.1, as this subunit is similar in many respects.
Gene
GeneID: 257648 Cacna1b calcium channel, voltage-dependent, N type, alpha 1B subunit [ Rattus norvegicus ]
Transcript
Acc No | Sequence | Length | Source | |
---|---|---|---|---|
NM_001195199 | n/A | n/A | NCBI | |
NM_147141 | n/A | n/A | NCBI | |
NM_007579 | n/A | n/A | NCBI | |
NM_001042528 | n/A | n/A | NCBI | |
NM_000718 | n/A | n/A | NCBI |
Ontology
Accession | Name | Definition | Evidence | |||||||
---|---|---|---|---|---|---|---|---|---|---|
GO:0043198 | dendritic shaft | Cylindric portion of the dendrite, directly stemming from the perikaryon, and carrying the dendritic spines. | IDA | |||||||
GO:0005886 | plasma membrane | The membrane surrounding a cell that separates the cell from its external environment. It consists of a phospholipid bilayer and associated proteins. | IDA | |||||||
GO:0043025 | neuronal cell body | The portion of a neuron that includes the nucleus, but excludes all cell projections such as axons and dendrites. | IDA | |||||||
GO:0043679 | axon terminus | Terminal inflated portion of the axon, containing the specialized apparatus necessary to release neurotransmitters. The axon terminus is considered to be the whole region of thickening and the terminal button is a specialized region of it. | IDA | |||||||
GO:0005891 | voltage-gated calcium channel complex | A protein complex that forms a transmembrane channel through which calcium ions may pass in response to changes in membrane potential. | IEA | |||||||
GO:0016021 | integral to membrane | Penetrating at least one phospholipid bilayer of a membrane. May also refer to the state of being buried in the bilayer with no exposure outside the bilayer. When used to describe a protein, indicates that all or part of the peptide sequence is embedded in the membrane. | IEA | |||||||
GO:0019717 | synaptosome | Any of the discrete particles (nerve-ending particles) formed from the clublike presynaptic nerve endings that resist disruption and are snapped or torn off their attachments when brain tissue is homogenized in media isosmotic to plasma. | IDA | |||||||
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 |
G proteins
See figure 10 in [94] for the mechanism of G protein modulation in calcium channels and the effect of palmitoylation on the interaction of Cav-beta subunits with the I–II linker.
Neurokinin 1 Receptor
Unlike R-type channels encoded by CaV2.3, L-type (CaV1.3), N- type (CaV2.2), and P/Q-type (CaV2.1) channels are inhibited, but not stimulated, through Neurokinin 1 receptors. [89]
Beta 3 Subunit
Overexpressed beta 3 subunit (12.5 ng/cell cRNA) significantly suppressed N- and R-type, but not L-type calcium channel currents at holding potentials of 60 and 80 mV.[92]
Roscovitine
Roscovitine, a potent inhibitor of cyclin-dependent kinases 1, 2, and 5, slows the deactivation of P/Q (Cav2.1) and N-type (Cav2.2) calcium channels. [93]
Protein
The Cav2.2 subunit consists of four homologous domains (I–IV), each consisting of six trans- membrane (TM) segments. The domains are linked by intracellular loops and have intracellular N and C termini. (see Fig. 1A) in [88]
See also figure 7 in [90] for a structural connection between Cav2.1 and Cav2.2.
Distribution
presynaptic
Cav2.2 can be found in retinal ganglion cells. [259]
Cav2.2 control the excitability in retinal ganglion cells and thus are crucial for the development of the visual system. [250]
Kinetics
The most detailed model can be found in [250]. It is from hippocampal mossy fiber boutons.
For a Hodgkin Huxley rate equation for the Ca2.2 (= N-type) current, see [260].
Model CaN (ID=6) Edit
Animal | Cat | |
CellType | RGC | |
Age | 34 Days | |
Temperature | 36.0°C | |
Reversal | 135.0 mV | |
Ion | Ca + | |
Ligand ion | ||
Reference | S J Huang et. al; Neuroscience 1998 Jul | |
mpower | 2.0 | |
m Alpha | (0.1*(v-20)/(1-exp(-(v-20)/10))) If v neq 20 | |
m Beta | 0.4*exp(-(v+25)/18) | |
hpower | 1.0 | |
h Alpha | 0.01*exp(-(v+50)/10) | |
h Beta | 0.1/(1+exp(-(v+17)/17)) |
References
Page KM
et al.
N terminus is key to the dominant negative suppression of Ca(V)2 calcium channels: implications for episodic ataxia type 2.
J. Biol. Chem.,
2010
Jan
8
, 285 (835-44).
Meza U
et al.
Neurokinin 1 receptors trigger overlapping stimulation and inhibition of CaV2.3 (R-type) calcium channels.
Mol. Pharmacol.,
2007
Jan
, 71 (284-93).
Vitko I
et al.
Orientation of the calcium channel beta relative to the alpha(1)2.2 subunit is critical for its regulation of channel activity.
PLoS ONE,
2008
, 3 (e3560).
Yasuda T
et al.
Overexpressed Ca(v)beta3 inhibits N-type (Cav2.2) calcium channel currents through a hyperpolarizing shift of ultra-slow and closed-state inactivation.
J. Gen. Physiol.,
2004
Apr
, 123 (401-16).
Buraei Z
et al.
Slowed N-type calcium channel (CaV2.2) deactivation by the cyclin-dependent kinase inhibitor roscovitine.
Biophys. J.,
2005
Sep
, 89 (1681-91).
95
Helton TD
et al.
Neuronal L-type calcium channels open quickly and are inhibited slowly.
J. Neurosci.,
2005
Nov
2
, 25 (10247-51).
96
Raghib A
et al.
Dominant-negative synthesis suppression of voltage-gated calcium channel Cav2.2 induced by truncated constructs.
J. Neurosci.,
2001
Nov
1
, 21 (8495-504).
Li L
et al.
Differential gating and recruitment of P/Q-, N-, and R-type Ca2+ channels in hippocampal mossy fiber boutons.
J. Neurosci.,
2007
Dec
5
, 27 (13420-9).
Huang SJ
et al.
Activation and inactivation properties of voltage-gated calcium currents in developing cat retinal ganglion cells.
Neuroscience,
1998
Jul
, 85 (239-47).
Benison G
et al.
Modeling temporal behavior of postnatal cat retinal ganglion cells.
J. Theor. Biol.,
2001
May
21
, 210 (187-99).
Catterall WA
Structure and regulation of voltage-gated Ca2+ channels.
Annu. Rev. Cell Dev. Biol.,
2000
, 16 (521-55).
478
Black JL
The voltage-gated calcium channel gamma subunits: a review of the literature.
J. Bioenerg. Biomembr.,
2003
Dec
, 35 (649-60).
555
Mintz IM
et al.
Block of calcium channels in rat neurons by synthetic omega-Aga-IVA.
Neuropharmacology,
1993
Nov
, 32 (1161-9).
Credits
Contributors: Rajnish Ranjan, Michael Schartner
To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/ionchannels/79/ , accessed on [date]