Title: A novel potassium channel in lymphocyte mitochondria.

Authors: Ildikò Szabò, Jürgen Bock, Andreas Jekle, Matthias Soddemann, Constantin Adams, Florian Lang, Mario Zoratti, Erich Gulbins

Journal, date & volume: J. Biol. Chem., 2005 Apr 1 , 280, 12790-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15632141

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.