The study identifies a specific, calmodulin-independent molecular interaction between the N-termini of Kv1.4 and Kv1.5 potassium channels and the spectrin repeats of α-actinin-2.
No immediate clinical implications for arrhythmia care; leaves open functional roles in cardiac repolarization pending in vivo validation.
The interaction between the amino terminus of Kv1‐type potassium channels and α‐actinin‐2 has been investigated. Using a combination of yeast two‐hybrid analysis and in vitro binding assays, α‐actinin‐2 was found to bind to the N‐termini of both Kv1.4 and Kv1.5 but not to the equivalent segments of Kv1.1, Kv1.2 or Kv1.3. Deletion analysis in the in vitro binding assays delineated the actinin binding region of Kv1.5 to between amino acids 73 and 148 of the channel. The Kv1.5 binding sites in α‐actinin‐2 were found to lie within actinin's internal spectrin repeats. Unlike the reported interaction between actinin and the NMDA receptor, calmodulin was found to have no effect on actinin binding to Kv1.5.
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Cukovic et al. (2001) studied this question.
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