Potassium channel toxin alpha-KTx 15.3

UniProtKB accession:  P60208

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UniProtKB description:  Inhibits A-type (Kv4) voltage-gated potassium channels of striated neurons (Ki=131 nM), probably by acting as a pore blocker (PubMed:12473099, PubMed:23440961, PubMed:30529150). Has also been shown to block ERG1/Kv11.1/KCNH2 potassium channels (IC(50)=7.9 uM) (PubMed:18687312). The presence of the Kv4-associated proteins DPP6 or DPP10 is mandatory to have high-affinity blockade of Kv4.2/KCND2 and Kv4.3/KCND3 channels (80-90% inhibition at 500 nM of toxin) (PubMed:23440961). In contrast, the presence of the Kv4-associated protein KChIP1/KCNIP1 does not enhance the affinity blockade (only 40% inhibition at 500 nM) (PubMed:23440961). In adult rat brain, the toxin binds to sites in the striatum, and cerebellum. It shares the same target in rat brain than AaTX1 (AC Q867F4) and BmTX3 (AC Q8I0L5). In DPP6 knockout mice, A-type currents are about 20-fold less affected by the toxin (PubMed:23440961). In rodent models of Parkinson's disease, the toxin reduces motor symptoms and emotional and cognitive symptoms (PubMed:25356731).