Molecular cloning and characterization of the human voltage-gated calcium channel alpha(2)delta-4 subunit.

Article Details

Citation

Qin N, Yagel S, Momplaisir ML, Codd EE, D'Andrea MR

Molecular cloning and characterization of the human voltage-gated calcium channel alpha(2)delta-4 subunit.

Mol Pharmacol. 2002 Sep;62(3):485-96.

PubMed ID
12181424 [ View in PubMed
]
Abstract

The voltage-gated calcium channel is composed of a pore-forming alpha(1) subunit and several regulatory subunits: alpha(2)delta, beta, and gamma. We report here the identification of a novel alpha(2)delta subunit, alpha(2)delta-4, from the expressed sequence tag database followed by its cloning and characterization. The novel alpha(2)delta-4 subunit gene contains 39 exons spanning about 130 kilobases and is co-localized with the CHCNA1C gene (alpha(1C) subunit) on human chromosome 12p13.3. Alternative splicing of the alpha(2)delta-4 gene gives rise to four potential variants, a through d. The open reading frame of human alpha(2)delta-4a is composed of 3363 base pairs encoding a protein with 1120 residues and a calculated molecular mass of 126 kDa. The alpha(2)delta-4a subunit shares 30, 32, and 61% identity with the human calcium channel alpha(2)delta-1, alpha(2)delta-2, and alpha(2)delta-3 subunits, respectively. Primary sequence comparison suggests that alpha(2)delta-4 lacks the gabapentin binding motifs characterized for alpha(2)delta-1 and alpha(2)delta-2; this was confirmed by a [(3)H]gabapentin-binding assay. In human embryonic kidney 293 cells, the alpha(2)delta-4 subunit associated with Ca(V)1.2 and beta(3) subunits and significantly increased Ca(V)1.2/beta(3)-mediated Ca(2+) influx. Immunohistochemical study revealed that the alpha(2)delta-4 subunit has limited distribution in special cell types of the pituitary, adrenal gland, colon, and fetal liver. Whether the alpha(2)delta-4 subunit plays a distinct physiological role in select endocrine tissues remains to be demonstrated.

DrugBank Data that Cites this Article

Polypeptides
NameUniProt ID
Voltage-dependent L-type calcium channel subunit alpha-1CQ13936Details
Voltage-dependent L-type calcium channel subunit beta-3P54284Details
Voltage-dependent calcium channel subunit alpha-2/delta-3Q8IZS8Details
Voltage-dependent calcium channel subunit alpha-2/delta-4Q7Z3S7Details