Referenced in: none

Automatically associated channels: ClC4

Title: CLC-Nt1, a putative chloride channel protein of tobacco, co-localizes with mitochondrial membrane markers.

Authors: C Lurin, J Güclü, C Cheniclet, J P Carde, H Barbier-Brygoo, C Maurel

Journal, date & volume: Biochem. J., 2000 Jun 1 , 348 Pt 2, 291-5

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/10816421

Abstract
The voltage-dependent chloride channel (CLC) family of membrane proteins has cognates in animals, yeast, bacteria and plants, and chloride-channel activity has been assigned to most of the animal homologues. Lack of evidence of CLC functions in plants prompted us to characterize the cellular localization of the tobacco CLC-Nt1 protein. Specific polyclonal antibodies were raised against an N-terminal polypeptide of CLC-Nt1. These antibodies were used to probe membrane proteins prepared by various cell-fractionation methods. These included aqueous two-phase partitioning (for plasma membranes), free-flow electrophoresis (for vacuolar and plasma membranes), intact vacuole isolation, Percoll-gradient centrifugation (for plastids and mitochondria) and stepped, linear, sucrose-density-gradient centrifugation (for mitochondria). Each purified membrane fraction was characterized with specific marker enzyme activities or antibodies. Our studies ruled out the possibility that the major cell localization of CLC-Nt1 was the vacuolar or plasma membranes, the endoplasmic reticulum, the Golgi apparatus or the plastids. In contrast, we showed that the tobacco CLC-Nt1 specifically co-localized with the markers of the mitochondrial inner membrane, cytochrome c oxidase and NAD9 protein. CLC-Nt1 may correspond to the inner membrane anion channel ('IMAC') described previously in animal and plant mitochondria.