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Palmitoylation of large conductance calcium‐ and voltage activated potassium (BK) channel β‐subunits
Author(s) -
Bi Danlei,
Chen Lie,
McClafferty Heather,
Tian Lijun,
Shipston Mike
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.913.26
Subject(s) - palmitoylation , bk channel , hek 293 cells , microbiology and biotechnology , potassium channel , cav1.2 , chemistry , cysteine , biophysics , intracellular , calcium activated potassium channel , alanine , biology , biochemistry , protein subunit , amino acid , gene , enzyme
BK channels control diverse physiological functions including vascular tone and neuronal excitability. In these tissues, BK channel pore‐forming α‐subunits (α) typically assemble with regulatory β‐subunits (β). Though the properties of α are regulated by a range of post‐translational modifications (PTMs) like S‐acylation, whether β are also modified by this PTM is unknown. We predicted that both β1 and β4 were palmitoylated and confirmed it by 3 H‐Palmitate incorporation and acyl‐RAC assays. We investigated the effect of palmitoylation of the β1 and β4 on the trafficking and activity of theα ZERO variant in HEK293 cells by quantitative immunofluorescence imaging and patch clamping. The cell surface expression of ZERO was significantly enhanced upon co‐expression of either β1 or β4 (>;100% by β1 and >;50% by β4). Depalmitoylation of β4, but not β1, by mutation of a single cysteine residue to alanine, significantly reduced co‐expressed ZERO variant surface expression. In macropatch recordings, co‐expression of wild‐type β1 and β4 significantly left‐shifted the V 0.5max of the channels as expected at 10uM intracellular free calcium. However, depalmitoylation of either βdid not significantly affect the normal left‐shift of V 0.5max. These data suggest that palmitoyaltion is crucial for trafficking of BKα upon β4, but not β1, but not their effect on V 0.5max . The functional role of β1 pamitoylation is to be determined. The work is supported by Wellcome Trust and The China Scholarship Council.