Evidence for the intracellular location of chloride channel (ClC)-type proteins: co-localization of ClC-6a and ClC-6c with the sarco/endoplasmic-reticulum Ca2+ pump SERCA2b

摘要: Chloride channel protein (ClC)-6a and ClC-6c, a kidney-specific splice variant with truncated C-terminus, are proteins that belong structurally to the family of voltage-dependent chloride channels. Attempts characterize functionally ClC-6a or ClC-6c in Xenopus oocytes have so far been negative. Similarly, expression both ClC-6 isoforms mammalian cells failed provide functional information. One possible explanation these negative results is an intracellular rather than being located plasma membrane. We therefore studied subcellular location by transiently transfecting COS CHO epitope-tagged versions ClC-6c. Confocal imaging transfected revealed for distribution pattern clearly differed from peripheral CD2, plasma-membrane glycoprotein. Furthermore, dual-labelling experiments co-transfected -6c sarco/endoplasmic-reticulum Ca2+ pump (SERCA2b) indicated co-localized SERCA2b pump. Thus membrane proteins, most likely residing endoplasmic reticulum. In view their structural similarity proven channels, molecular candidates