Membrane trafficking of large conductance calcium-activated potassium channels is regulated by alternative splicing of a transplantable, acidic trafficking motif in the RCK1-RCK2 linker

Chen, L., Jeffries, O., Rowe, I. C. M. , Liang, Z., Knaus, H.-G., Ruth, P. and Shipston, M. J. (2010) Membrane trafficking of large conductance calcium-activated potassium channels is regulated by alternative splicing of a transplantable, acidic trafficking motif in the RCK1-RCK2 linker. Journal of Biological Chemistry, 285(30), pp. 23265-23275. (doi: 10.1074/jbc.M110.139758) (PMID:20479001) (PMCID:PMC2906319)

Abstract

Trafficking of the pore-forming α-subunits of large conductance calcium- and voltage-activated potassium (BK) channels to the cell surface represents an important regulatory step in controlling BK channel function. Here, we identify multiple trafficking signals within the intracellular RCK1-RCK2 linker of the cytosolic C terminus of the channel that are required for efficient cell surface expression of the channel. In particular, an acidic cluster-like motif was essential for channel exit from the endoplasmic reticulum and subsequent cell surface expression. This motif could be transplanted onto a heterologous nonchannel protein to enhance cell surface expression by accelerating endoplasmic reticulum export. Importantly, we identified a human alternatively spliced BK channel variant, hSloΔ579–664, in which these trafficking signals are excluded because of in-frame exon skipping. The hSloΔ579–664 variant is expressed in multiple human tissues and cannot form functional channels at the cell surface even though it retains the putative RCK domains and downstream trafficking signals. Functionally, the hSloΔ579–664 variant acts as a dominant negative subunit to suppress cell surface expression of BK channels. Thus alternative splicing of the intracellular RCK1-RCK2 linker plays a critical role in determining cell surface expression of BK channels by controlling the inclusion/exclusion of multiple trafficking motifs.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rowe, Dr Iain
• Authors: Chen, L., Jeffries, O., Rowe, I. C. M., Liang, Z., Knaus, H.-G., Ruth, P., and Shipston, M. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Life Sciences
• Journal Name: Journal of Biological Chemistry
• Publisher: Elsevier
• ISSN: 0021-9258
• ISSN (Online): 1083-351X
• Published Online: 17 May 2010
• Copyright Holders: Copyright © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
• First Published: First published in Journal of Biological Chemistry 285(30): 23265-23275
• Publisher Policy: Reproduced under a Creative Commons licence