Different effects of the Ca(2+)-binding protein, KChIP1, on two Kv4 subfamily members, Kv4.1 and Kv4.2.
The Ca(2+)-binding protein, K(+) channel-interacting protein 1 (KChIP1), modulates Kv4 channels. We show here that KChIP1 affects Kv4.1 and Kv4.2 currents differently. KChIP1 slows Kv4.2 inactivation but accelerates the Kv4.1 inactivation time course. Kv4.2 activation is shifted in a hyperpolarizing direction, whereas a depolarizing shift occurs for Kv4.1. On the other hand, KChIP1 increases the current amplitudes and accelerates recovery from inactivation of both currents. An involvement of the Kv4 N-terminus in these differential effects is demonstrated using chimeras of Kv4.2 and Kv4.1. These results reveal a novel interaction of KChIP1 with these two Kv4 members. This represents a mechanism to further increase the functional diversity of K(+) channels.
Nakamura
T Y
TY
Pediatric Cardiology, NYU School of Medicine, NY 10016, USA. tomoe.nishitani@med.nyu.edu
Nandi
S
S
Pountney
D J
DJ
Artman
M
M
Rudy
B
B
Coetzee
W A
WA
D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004594:Electrophysiology; D051605:Kv Channel-Interacting Proteins; D009865:Oocytes / Q000502:physiology; D015221:Potassium Channels / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated; D051672:Shal Potassium Channels; D014162:Transfection; D014982:Xenopus laevis
D002135:Calcium-Binding Proteins; C497015:KCND1 protein, human; D051605:Kv Channel-Interacting Proteins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051672:Shal Potassium Channels