voltage-dependent Ca+2 channel subunit alpha-2/delta-4 (voltage-gated Ca+2 channel subunit alpha-2/delta-4, [Contains: Voltage-dependent Ca+2 channel subunit alpha-2-4; Voltage-dependent Ca+2 channel subunit delta-4], CACNA2D4)
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Function
- alpha-2/delta subunit of voltage-dependent Ca+2 channels regulates Ca+2 current density & activation/inactivation kinetics of the Ca+2 channel
- dimer formed of alpha-2-2 & delta-2 chains; disulfide-linked
- voltage-dependent Ca+2 channels are multisubunit complexes, consisting of alpha-1 (CACNA1), alpha-2 (CACNA2D), beta (CACNB) & delta (CACNA2D) subunits in a 1:1:1:1 ratio
- interacts with CACNA1C & CACNB3
- may be proteolytically processed into subunits alpha-2-4 & delta-4 that are disulfide-linked; however, unclear whether cleavage really takes place in vivo & has a functional role
- in contrast to CACNA2D1 & CACNA2D2, it does not bind gabapentin
Structure
- MIDAS-like motif in the VWFA domain binds divalent metal cations & is required to promote trafficking of the alpha-1 (CACNA1) subunit to the plasma membrane by an integrin-like switch (putative)
- belongs to the Ca+2 channel subunit alpha-2/delta family
- contains 1 cache domain
- contains 1 VWFA domain
Compartment
membrane (putative)
Alternative splicing
named isoforms=6
Expression
- predominantly expressed in certain types of endocrine cells
- present in the Paneth cells of the small intestine
- also present in the erythroblasts in the fetal liver, in the cells of the zona reticularis of the adrenal gland & in the basophiles of the pituitary
- present at low level in some brain regions such as the cerebellum (at protein level)
Pathology
- defects in CACNA2D4 are the cause of retinal cone dystrophy 4