6l6i

Structural highlights

Function

ASIC1_HUMAN Isoform 2 and isoform 3 function as proton-gated sodium channels; they are activated by a drop of the extracellular pH and then become rapidly desensitized. The channel generates a biphasic current with a fast inactivating and a slow sustained phase. Has high selectivity for sodium ions and can also transport lithium ions with high efficiency. Isoform 2 can also transport potassium, but with lower efficiency. It is nearly impermeable to the larger rubidium and cesium ions. Isoform 3 can also transport calcium ions. Mediates glutamate-independent Ca(2+) entry into neurons upon acidosis. This Ca(2+) overloading is toxic for cortical neurons and may be in part responsible for ischemic brain injury. Heteromeric channel assembly seems to modulate channel properties. Functions as a postsynaptic proton receptor that influences intracellular Ca(2+) concentration and calmodulin-dependent protein kinase II phosphorylation and thereby the density of dendritic spines. Modulates activity in the circuits underlying innate fear.^[1] Isoform 1 does not display proton-gated cation channel activity.^[2]

See Also

• Ion channels 3D structures

References

1. ↑ Dawson RJ, Benz J, Stohler P, Tetaz T, Joseph C, Huber S, Schmid G, Hugin D, Pflimlin P, Trube G, Rudolph MG, Hennig M, Ruf A. Structure of the Acid-sensing ion channel 1 in complex with the gating modifier Psalmotoxin 1. Nat Commun. 2012 Jul 3;3:936. doi: 10.1038/ncomms1917. PMID:22760635 doi:10.1038/ncomms1917
2. ↑ Dawson RJ, Benz J, Stohler P, Tetaz T, Joseph C, Huber S, Schmid G, Hugin D, Pflimlin P, Trube G, Rudolph MG, Hennig M, Ruf A. Structure of the Acid-sensing ion channel 1 in complex with the gating modifier Psalmotoxin 1. Nat Commun. 2012 Jul 3;3:936. doi: 10.1038/ncomms1917. PMID:22760635 doi:10.1038/ncomms1917