Current inhibition of human EAG1 potassium channels by the Ca2+ binding protein S100B.
Voltage-dependent human ether à go-go (hEAG1) potassium channels are implicated in neuronal signaling as well as in cancer cell proliferation. Unique sensitivity of the channel to intracellular Ca(2+) is mediated by calmodulin (CaM) binding to the intracellular N- and C-termini of the channel. Here we show that application of the acidic calcium-binding protein S100B to inside-out patches of Xenopus oocytes causes Ca(2+)-dependent inhibition of expressed hEAG1 channels. Protein pull-down assays and fluorescence correlation spectroscopy (FCS) revealed that S100B binds to hEAG1 and shares the same binding sites with CaM. Thus, S100B is a potential alternative calcium sensor for hEAG1 potassium channels.
Sahoo
Nirakar
N
Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University of Jena, Jena, Germany. nirakarbiot@gmail.com
Tröger
Jessica
J
Heinemann
Stefan H
SH
Schönherr
Roland
R
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D051638:Ether-A-Go-Go Potassium Channels / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D009414:Nerve Growth Factors / Q000378:metabolism*; D009865:Oocytes; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*; D014981:Xenopus
D051638:Ether-A-Go-Go Potassium Channels; C496884:KCNH1 protein, human; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human; D002118:Calcium