14-3-3θ is a binding partner of rat Eag1 potassium channels.
The ether-à-go-go (Eag) potassium (K(+)) channel belongs to the superfamily of voltage-gated K(+) channel. In mammals, the expression of Eag channels is neuron-specific but their neurophysiological role remains obscure. We have applied the yeast two-hybrid screening system to identify rat Eag1 (rEag1)-interacting proteins from a rat brain cDNA library. One of the clones we identified was 14-3-3θ, which belongs to a family of small acidic protein abundantly expressed in the brain. Data from in vitro yeast two-hybrid and GST pull-down assays suggested that the direct association with 14-3-3θ was mediated by both the N- and the C-termini of rEag1. Co-precipitation of the two proteins was confirmed in both heterologous HEK293T cells and native hippocampal neurons. Electrophysiological studies showed that over-expression of 14-3-3θ led to a sizable suppression of rEag1 K(+) currents with no apparent alteration of the steady-state voltage dependence and gating kinetics. Furthermore, co-expression with 14-3-3θ failed to affect the total protein level, membrane trafficking, and single channel conductance of rEag1, implying that 14-3-3θ binding may render a fraction of the channel locked in a non-conducting state. Together these data suggest that 14-3-3θ is a binding partner of rEag1 and may modulate the functional expression of the K(+) channel in neurons.
Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Po-Hao
PH
Hsu
Shi-Chuen
SC
Miaw
Chau-Ching
CC
Chuang
Pei-Yu
PY
Chang
Ssu-Ju
SJ
Fu
Guey-Mei
GM
Jow
Mei-Miao
MM
Chiu
Chung-Jiuan
CJ
Jeng
D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins; D002460:Cell Line; D051638:Ether-A-Go-Go Potassium Channels / Q000737:chemistry / Q000378:metabolism*; D015870:Gene Expression; D023061:Gene Order; D006801:Humans; D009474:Neurons / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D051381:Rats
D048948:14-3-3 Proteins; D002352:Carrier Proteins; D051638:Ether-A-Go-Go Potassium Channels; C496886:Kcnh1 protein, rat