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J Biol Chem. 2005 Apr 1;280(13):12790-8. Epub 2005 Jan 4.

A novel potassium channel in lymphocyte mitochondria.

Author information

1
Department of Biology, University of Padova, 35121 Padova, Italy. ildi@civ.bio.unipd.it

Abstract

The margatoxin-sensitive Kv1.3 is the major potassium channel in the plasma membrane of T lymphocytes. Electron microscopy, patch clamp, and immunological studies identified the potassium channel Kv1.3, thought to be localized exclusively in the cell membrane, in the inner mitochondrial membrane of T lymphocytes. Patch clamp of mitoplasts and mitochondrial membrane potential measurements disclose the functional expression of a mitochondrial margatoxin-sensitive potassium channel. To identify unambiguously the mitochondrial localization of Kv1.3, we employed a genetic model and stably transfected CTLL-2 cells, which are genetically deficient for this channel, with Kv1.3. Mitochondria isolated from Kv1.3-reconstituted CTLL-2 expressed the channel protein and displayed an activity, which was identical to that observed in Jurkat mitochondria, whereas mitochondria of mock-transfected cells lacked a channel with the characteristics of Kv1.3. Our data provide the first molecular identification of a mitochondrial potassium conductance.

PMID:
15632141
DOI:
10.1074/jbc.M413548200
[Indexed for MEDLINE]
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