Voltage-dependent Ca+2 channel subunit alpha-2/delta-2 (voltage-gated Ca+2 channel subunit alpha-2/delta-2, [Contains: Voltage-dependent Ca+2 channel subunit alpha-2-2; Voltage-dependent Ca+2 channel subunit delta-2], CACNA2D2, KIAA0558)
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Function
- alpha-2/delta subunit of voltage-dependent Ca+2
- channels regulates Ca+ current density & activation/inactivation kinetics of the Ca+2 channel
- regulatory subunit for P/Q-type Ca+2 channel (CACNA1A), N-type (CACNA1B), L-type (CACNA1C OR CACNA1D) & possibly T-type (CACNA1G)
- 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
- may be proteolytically processed into subunits alpha-2-2 & delta-2, disulfide-linked; however, unclear whether cleavage occurs in vivo & has a functional role
- overexpression induces apoptosis
- binds gabapentin
Structure
- N-glycosylated
- MIDAS-like motif in the VWFA domain binds divalent metal cations & is required to promote trafficking of 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)
- colocalizes with CACNA1A in lipid raft fractions (putative)
Alternative splicing
named isoforms=5
Expression
- predominantly present in cerebellar cortex
- highly expressed in heart, lung, testis, pancreas & s keletal muscle
- also expressed in kidney, liver, placenta & brain
Pathology
- expressed various lung tumor cell lines, but absent in normal lung (at protein level)