Description: calcium channel, voltage-dependent, beta 3 subunit
Gene: Cacnb3     Synonyms: cacnb3

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Voltage dependent calcium channels (VDCC) auxiliary beta (Cavb1–4) and alpha2delta (Cava2d1–4) subunits associate with the alpha1 functional subunits (for review see Walker and De Waard, 1998 [1279]) and affect the biophysical properties of the alpha1 subunits as observed for the auxiliary subunits of voltage-dependent sodium and potassium channels (for review see Isom et al., 1994 [1247]; Trimmer, 1998 [1280]).

Experimental data

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CACNB3 (also known as CAB3; CACNLB3; FLJ58949) encodes beta 3 subunit of voltage dependent calcium channels.

RGD ID Chromosome Position Species
2248 7 137384752-137394283 Rat
10270 15 98462651-98474961 Mouse
735859 12 49212512-49222724 Human

Cacnb3 : calcium channel, voltage-dependent, beta 3 subunit



Acc No Sequence Length Source
NM_012828 n/A n/A NCBI
NM_007581 n/A n/A NCBI
NM_001044741 n/A n/A NCBI
NM_000725 n/A n/A NCBI



Accession Name Definition Evidence
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
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. IDA
GO:0016324 apical plasma membrane The region of the plasma membrane located at the apical end of the cell. 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





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High-voltage–activated calcium channels are comprised of a pore-forming alpha1 subunit, auxiliary beta and alpha2delta subunits, and, in some cases, an auxiliary gamma subunit (for review see Catterall, 2000 [477]).

The b subunit has been shown to interact with alpha1 subunit interaction domain (AID) in the cytoplasmic I-II linker of alpha1 subunit (Pragnell et al., 1994 [1290]; Witcher et al., 1995 [1291]), and all four beta subunits interacted with AID of Cav2.2-alpha-1 in vitro with high affinity (Kd of 5nM; Scott et al., 1996 [1292]).





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It has been shown that b auxiliary subunits increase current amplitude in voltage-dependent calcium channels (Mori et al., 1991; Neely et al., 1993 [1241]; Wakamori et al., 1993 [1286]; Jones et al., 1998 [1266]; Klugbauer et al., 1999 [1289]). However, Yasuda et al. [92] found a novel inhibitory effect of b3 subunit on macroscopic Ba2+ currents through recombinant N- and R-type calcium channels expressed in Xenopus oocytes.

Coexpression of beta subunits enhanced the level of channel expression in the plasma membrane (Williams et al., 1992 [1281]; Brust et al., 1993 [1282]) by chaperoning the translocation of alpha1 subunits (Chien et al., 1995 [1261]; Yamaguchi et al., 1998 [238]; Gao et al., 1999 [1283]; Gerster et al., 1999 [1284]) from ER where beta subunits antagonize the binding between alpha1 and an ER retention protein (Bichet et al., 2000 [1285]). In addition, beta subunits also increased channel open probability without affecting single-channel conductance (Neely et al., 1993 [1221]; Wakamori et al., 1993 [1286], 1999 [1287]; Jones et al., 1998 [1266]; Gerster et al., 1999 [1284]; Hohaus et al., 2000 [1288]). A hyperpolarizing shift of I-V relationships by beta subunits (Neely et al., 1993 [1241]; Yamaguchi et al., 1998 [238]) also partially contributes to an increase in macroscopic current amplitude.







Catterall WA. et al. Structure and regulation of voltage-gated Ca2+ channels.
Annu. Rev. Cell Dev. Biol., 2000 , 16 (521-55).

De Waard M. et al. Subunit interaction sites in voltage-dependent Ca2+ channels: role in channel function.
Trends Neurosci., 1998 Apr , 21 (148-54).

Catterall WA. et al. Auxiliary subunits of voltage-gated ion channels.
Neuron, 1994 Jun , 12 (1183-94).

Trimmer JS. et al. Regulation of ion channel expression by cytoplasmic subunits.
Curr. Opin. Neurobiol., 1998 Jun , 8 (370-4).

Jones LP. et al. Mechanism of auxiliary subunit modulation of neuronal alpha1E calcium channels.
J. Gen. Physiol., 1998 Aug , 112 (125-43).

Hofmann F. et al. Molecular diversity of the calcium channel alpha2delta subunit.
J. Neurosci., 1999 Jan 15 , 19 (684-91).

De Waard M. et al. Association of native Ca2+ channel beta subunits with the alpha 1 subunit interaction domain.
J. Biol. Chem., 1995 Jul 28 , 270 (18088-93).

Scott VE. et al. Beta subunit heterogeneity in N-type Ca2+ channels.
J. Biol. Chem., 1996 Feb 9 , 271 (3207-12).