Kir6.2ΔC26 Channel Traffics to Plasma Membrane by Constitutive Exocytosis  

作　　者：Ping ZHAO Wei LI Yong-Ming DONG Dan ZHU An-Lian QU Tao XU Zheng-Xing WU 

机构地区：[1]Institute of Biophysics and Biochemistry, Huazhong University of Science and Technology, Wuhan 430074, China

出　　处：《Acta Biochimica et Biophysica Sinica》2006年第2期136-141,共6页生物化学与生物物理学报（英文版）

基　　金：This work supported by a grant from the National Natural Science Foundation of China （No. 30470448, 30130230 and 30270363） and the Specialized Research Foundation for the Doctoral Program of Higher Education （No. 2002487021）

摘　　要：Adenosine triphosphate （ATP）-sensitive K^＊ （KATP） channels regulate many cellular functions by coupling the metabolic state of the cell to the changes in membrane potential. Truncation of C-terminal 26 amino acid residues of Kir6.2 protein （Kir6.2ΔC26） deletes its endoplasmic reticulum retention signal, allowing functional expression of Kit6.2 in the absence of sulfonylurea receptor subunit, pEGFP-Kir6.2ΔC26 and pKir6.2ΔC26-IRES2-EGFP expression plasmids were constructed and transfected into HEK293 cells. We identified that Kir6.2ΔC26 was localized on the plasma membrane and trafficked to the plasmalemma by means of constitutive exocytosis of Kir6.2ΔC26 transport vesicles, using epi-fluorescence and total intemal reflection fluorescence microscopy. Our electrophysiological data showed that Kir6.2ΔC26 alone expressed KATP currents, whereas EGFP-Kir6.2ΔC26 fusion protein displayed no KATP channel activity.Adenosine triphosphate （ATP）-sensitive K^＊ （KATP） channels regulate many cellular functions by coupling the metabolic state of the cell to the changes in membrane potential. Truncation of C-terminal 26 amino acid residues of Kir6.2 protein （Kir6.2ΔC26） deletes its endoplasmic reticulum retention signal, allowing functional expression of Kit6.2 in the absence of sulfonylurea receptor subunit, pEGFP-Kir6.2ΔC26 and pKir6.2ΔC26-IRES2-EGFP expression plasmids were constructed and transfected into HEK293 cells. We identified that Kir6.2ΔC26 was localized on the plasma membrane and trafficked to the plasmalemma by means of constitutive exocytosis of Kir6.2ΔC26 transport vesicles, using epi-fluorescence and total intemal reflection fluorescence microscopy. Our electrophysiological data showed that Kir6.2ΔC26 alone expressed KATP currents, whereas EGFP-Kir6.2ΔC26 fusion protein displayed no KATP channel activity.

关 键 词：Kir6.2AC26 EXOCYTOSIS whole-cell current total internal reflection fluorescence microscopy patch clamp 

分 类 号：R329[医药卫生—人体解剖和组织胚胎学]