Fast inactivation in potassium channels: an interplay of cytoplasmic domains.
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.
Sankaranarayanan
Kavitha
K
National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS-GKVK Campus, GKVK P.O., Bangalore 560065, India.
Usman
Hyder
H
Mathew
M K
MK
D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D009865:Oocytes; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis
D015221:Potassium Channels; D011993:Recombinant Fusion Proteins