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Cell Biochem Biophys. 2011 Dec;61(3):585-94. doi: 10.1007/s12013-011-9241-1.

Background K(2P) channels KCNK3/9/15 limit the budding of cell membrane-derived vesicles.

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Department of Pediatrics, Mackay Memorial Hospital, Tamsui 251, Taiwan.


The main function of background two-pore potassium (K(2P)) channels KCNK3/9/15 is to stabilize the cell membrane potential. We previously observed that membrane potential depolarization enhances the release of HIV-1 viruses. Because membrane polarization affects the biomembrane directly, here we examined the effects of KCNK3/9/15 on the budding of nonviral vesicles. We found that depolarization by knocking down endogenous KCNK3/9/15 promoted secretion of cell-derived vesicles. We further used Vpu (an antagonist of KCNK3) as a model for the in vivo study of depolarization-stimulated secretion. Vpu is a HIV-1-encoded, ion channel-like protein (viroporin) capable of enhancing virus release and depolarizing the cell membrane potential. We found that Vpu could also promote nonviral vesicle release, perhaps through a similar mechanism that Vpu utilizes to promote viral particle release. Notably, T cells expressing Vpu alone became pathologically low in intracellular K(+) and insensitive to extracellular K(+) or membrane potential stimulation. In contrast, heterologous expression of KCNK3 in T cells stabilized the cell potentials by maintaining intracellular K(+). We thus concluded that KCNK3/9/15 expression limits membrane depolarization and depolarization-induced secretion at least in part by maintaining intracellular K(+).

[Indexed for MEDLINE]

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