- 作者: Jay-Ron Lee; Ru-Chi Shieh
- 作者服務機構: Institute of Biomedical Sciences Academia Sinica Taipei 11529, Taiwan, Republic of China
- 中文摘要: --
- 英文摘要:
Kir1.1 channels are important in maintaining K+ homeostasis in the kidney.
Intracellular acidification reversibly closes the Kir1.1 channel and thus decreases K+
secretion. In this study, we used Foster resonance energy transfer (FRET) to determine
whether the conformation of the cytoplasmic pore changes in response to intracellular pH
(pHi)-gating in Kir1.1 channels fused with enhanced cyan fluorescent protein (ECFP) and
enhanced yellow fluorescent protein (EYFP) (ECFP-Kir1.1-EYFP). Because the
fluorescence intensities of ECFP and EYFP were affected at pHi < 7.4 where pHi-gating
occurs in the ECFP-Kir1.1-EYFP construct, we examined the FRET efficiencies of an
ECFP-S219R-EYFP mutant, which is completed closed at pHi 7.4 and open at pHi 10.0.
FRET efficiency was increased from 25% to 40% when the pHi was decreased from 10.0
to 7.4. These results suggest that the conformation of the cytoplasmic pore in the Kir1.1
channel changes in response to pHi gating such that the N- and C-termini move apart
from each other at pHi 7.4, when the channel is open. - 中文關鍵字: --
- 英文關鍵字: --