Evaluation of channel function after alteration of amino acid residues at the pore center of KCNQ1 channel.
The effect of the electrical charge or the size of the amino acid residue at the pore center of a slowly activation component of the delayed rectifier potassium channel: KCNQ1 was studied. K(+) currents were measured after transfection of one of four KCNQ1 mutants: substituting Isoleucine with Lysine, Glutamate, Valine or Glycine and then transfected in COS-7 cells. Both the negatively- and positive charged residue I313K and I313E showed a loss of function when expressed alone and a dominant negative suppression when co-expressed with wild type KCNQ1. When the site was substituted with the smallest neutral amino acid residue: I313G, there was a small reduction of current when transfected alone and a gain of function when co-transfected with the wild type. I313V showed no difference from the wild type. Changes of amino acid residue at the pore center of KCNQ1 may alter the channel function but this depends on the electrical charge or the size of amino acid residue.
Ikrar
Taruna
T
Division of Cardiology, First Department of Internal Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-754 Asahimachi Dori, Chuo-ku, Niigata 951-8510, Japan.
Hanawa
Haruo
H
Watanabe
Hiroshi
H
Aizawa
Yoshiyasu
Y
Ramadan
Mahmoud M
MM
Chinushi
Masaomi
M
Horie
Minoru
M
Aizawa
Yoshifusa
Y
D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D018698:Glutamic Acid / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007532:Isoleucine / Q000235:genetics / Q000378:metabolism*; D051657:KCNQ1 Potassium Channel / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016062:Porosity; D055672:Static Electricity
D051657:KCNQ1 Potassium Channel; D007532:Isoleucine; D018698:Glutamic Acid; D008239:Lysine