Protein Domain : IPR008054

Type:  Family Name:  Voltage gated sodium channel, alpha-8 subunit
Description:  Voltage-dependent sodium channels are transmembrane (TM) proteins responsible for the depolarising phase of the action potential in mostelectrically excitable cells []. They may exist in 3 states []: theresting state, where the channel is closed; the activated state, where the channel is open; and the inactivated state, where the channel is closedand refractory to opening. Several different structurally and functionally distinct isoforms are found in mammals, coded for by a multigene family, these being responsible for the different types of sodium ion currentsfound in excitable tissues. The structure of sodium channels is based on 4 internal repeats of a 6-helix bundle [] (in which 5 of the membrane-spanning segments are hydrophobic andthe other is positively charged), forming a 24-helical bundle. The charged segments are believed to be localised within clusters formed by their 5 hydrophobic neighbours: it is postulated that the charged domain may be the voltage sensor region, possibly moving outward on depolarisation, causing aconformational change. This model [] contrastswith another [], in which the TM segments are juxtaposedoctagonally. The basic structural motif (the 6-helix bundle) is also found in potassium and calcium channel alpha subunits.The gene SCN8A encodes the voltage-gated Na+ channel alpha 8 subunit and is strongly expressed in Purkinje cells. Sodium currents are known to generatethe rising phase and the prolonged plateau phase of cerebellar purkinje cell action potentials. Experiments in mice with mutated SCN8A subunits suggestits involvement in the persistent sodium current responsible for the prolonged plateau phase []. The SCN8A gene is abundantly expressedthroughout the CNS and in the spinal cord. Mutations in mouse SCN8A result in a number of neurological disorders, including paralysis, ataxia anddystonia [].This entry represents a conserved region found towards the N terminus of the protein, which defines the alpha 8 subunits and distinguishes them from other members of the voltage-gated Na+ channel superfamily. For entries containing other members of this superfamily see , , . Short Name:  Na_channel_a8su

0 Child Features

3 Contains

DB identifier Type Name
IPR005821 Domain Ion transport domain
IPR000048 Binding_site IQ motif, EF-hand binding site
IPR010526 Domain Sodium ion transport-associated

1 Cross References

Identifier
PR01667

0 Found In

3 GO Annotations

GO Term Gene Name
GO:0005248 IPR008054
GO:0006814 IPR008054
GO:0001518 IPR008054

3 Ontology Annotations

GO Term Gene Name
GO:0005248 IPR008054
GO:0006814 IPR008054
GO:0001518 IPR008054

1 Parent Features

DB identifier Type Name
IPR001696 Family Voltage gated sodium channel, alpha subunit

0 Proteins

5 Publications

First Author Title Year Journal Volume Pages PubMed ID
            1323284
            6209577
            1317577
            9192691
            9698304