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Myelin basic protein as a binding partner and calmodulin adaptor for the BK Ca channel
Author(s) -
Kim Hyunyoung,
Jo Sooyeon,
Song HyeJin,
Park ZeeYong,
Park ChulSeung
Publication year - 2007
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200700185
Subject(s) - calmodulin , signal transducing adaptor protein , myelin basic protein , microbiology and biotechnology , binding protein , channel (broadcasting) , chemistry , computational biology , biology , biochemistry , myelin , neuroscience , signal transduction , computer science , telecommunications , enzyme , gene , central nervous system
The activity and localization of large‐conductance Ca 2+ ‐activated K + (BK Ca ) channels are known to be modulated by several different proteins. Although many binding partners have been identified via yeast two‐hybrid screening, this method may not detect certain classes of interacting proteins such as low affinity binding proteins or multi‐component protein complexes. In this study, we employed mass spectrometry to identify proteins that interact with BK Ca channels. We expressed and purified the ‘tail domain’ of the rat BK Ca channel α‐subunit, a 54‐kDa region that is crucial for expression and functional activity of the channel. Using rat brain lysate and purified ‘tail domain’, we identified several novel proteins that interact with the BK Ca channel. These included the myelin basic protein (MBP), upon which we performed subsequent biochemical and electrophysiological studies. Interaction between the BK Ca channel and MBP was confirmed in vivo and in vitro . MBP co‐expression affected the Ca 2+ ‐dependent activation of the BK Ca channel by increasing its Ca 2+ sensitivity. Moreover, we showed that calmodulin (CaM) interacts with the BK Ca channel via MBP. Since CaM is a key regulator of many Ca 2+ ‐dependent processes, it may be recruited by MBP to the vicinity of the BK Ca channel, modulating its functional activity.