Kir6.2DeltaC26 channel traffics to plasma membrane by constitutive exocytosis.
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 (Kir6.2DeltaC26) deletes its endoplasmic reticulum retention signal, allowing functional expression of Kir6.2 in the absence of sulfonylurea receptor subunit. pEGFP-Kir6.2DeltaC26 and pKir6.2DeltaC26-IRES2-EGFP expression plasmids were constructed and transfected into HEK293 cells. We identified that Kir6.2DeltaC26 was localized on the plasma membrane and trafficked to the plasmalemma by means of constitutive exocytosis of Kir6.2DeltaC26 transport vesicles, using epi-fluorescence and total internal reflection fluorescence microscopy. Our electrophysiological data showed that Kir6.2DeltaC26 alone expressed KATP currents, whereas EGFP-Kir6.2DeltaC26 fusion protein displayed no KATP channel activity.
Institute of Biophysics and Biochemistry, Huazhong University of Science and Technology, Wuhan 430074, China.
Ping
P
Zhao
Wei
W
Li
Yong-Ming
YM
Dong
Dan
D
Zhu
An-Lian
AL
Qu
Tao
T
Xu
Zheng-Xing
ZX
Wu
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004594:Electrophysiology; D005089:Exocytosis / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010957:Plasmids / Q000235:genetics; D015221:Potassium Channels / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D011955:Receptors, Drug / Q000378:metabolism; D064233:Sulfonylurea Receptors; D013997:Time Factors; D000099161:Kcnj11 Channel
D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate; D018076:DNA, Complementary; D049452:Green Fluorescent Proteins; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel; C485184:enhanced green fluorescent protein