Referenced in: none

Automatically associated channels: ClC3 , ClC4

Title: ClC-3B, a novel ClC-3 splicing variant that interacts with EBP50 and facilitates expression of CFTR-regulated ORCC.

Authors: Takehiko Ogura, Tetsushi Furukawa, Tetsuya Toyozaki, Katsuya Yamada, Ya-Juan Zheng, Yoshifumi Katayama, Haruaki Nakaya, Nobuya Inagaki

Journal, date & volume: FASEB J., 2002 Jun , 16, 863-5

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/11967229

Abstract
We have cloned ClC-3B, a novel alternative splicing variant of ClC-3 (ClC-3A) that is expressed predominantly in epithelial cells. ClC-3B has a different, slightly longer C-terminal end than ClC-3A and contains a consensus motif for binding to the second PDZ (PSD95/Dlg/ZO-1) domain of the epithelium-specific scaffolding protein EBP50. Both in vitro and in vivo binding assays demonstrate interaction between ClC-3B and EBP50. C127 mouse mammary epithelial cells transfected with ClC-3B alone showed diffuse immunoreactivity for ClC-3B in the cytoplasmic region. In contrast, when EBP50 was cotransfected with ClC-3B, strong immunoreactivity for ClC-3B appeared at the leading edges of membrane ruffles. Patch-clamp experiments revealed that cotransfection of ClC-3B and EBP50 resulted in a remarkable increase in outwardly rectifying Cl- channel (ORCC) activities at the leading edges of membrane ruffles in C127 cells. The electrophysiological properties of the ClC-3B-induced ORCCs are similar to those of ORCCs described in native epithelial cells. When cystic fibrosis transmembrane conductance regulator (CFTR) was cotransfected with ClC-3B and EBP50, ClC-3B-dependent ORCCs were activated via the protein kinase A-dependent pathway. These findings indicate that ClC-3B is itself a CFTR-regulated ORCC molecule or its activator.