Sankaranarayanan K, Usman H, Mathew MK. Fast inactivation in potassium channels: an interplay of cytoplasmic domains.
Biochem Biophys Res Commun 2009;
388:490-5. [PMID:
19665007 DOI:
10.1016/j.bbrc.2009.08.001]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Accepted: 08/02/2009] [Indexed: 11/27/2022]
Abstract
Fast inactivation in voltage-gated potassium channels has traditionally been associated exclusively with the N-terminus. Here, we explore the role of the T1 domain using a series of chimeric channels. A chimeric channel, 4N/2, (N-terminus from the rapidly inactivating hKv1.4, and the channel body from the non-inactivating hKv1.2), exhibited slower and incomplete inactivation as compared to the wild-type hKv1.4. Replacing the T1 domain of 4N2 with that from hKv1.2 (4N/2T1/2), restored inactivation, while that from hKv1.1 (4N/1T1/2) completely abolished inactivation. Based on these observations, we hypothesize a correlation between the tetramerization domain and the putative inactivation domain receptor in the process of rapid inactivation of hKv1 channels.
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