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Role of the scaffold protein striatin in regulating the excitation‐contraction coupling in cardiomyocytes
Author(s) -
Nader Moni,
Khalil Bariaa,
AbuZaid Ahmed,
Inaya A'man,
Bakheet Dana,
Dzimiri Nduna
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.1197.9
Subject(s) - protein phosphatase 2 , microbiology and biotechnology , calcium , phosphatase , calmodulin , chemistry , egta , calcium channel , biology , biochemistry , phosphorylation , organic chemistry
Striatin (STRN) is a multivalent protein with dynamic domains including caveolin (Cav) and calmodulin (CaM) binding sites; both of which are key regulators of the L‐type calcium channel (LCC). We have previously reported that the formation of the STRN/Cav/CaM complex was calcium sensitive and that overexpression of striatin resulted in a sustained elevation of KCl‐induced intracellular calcium increase. We aimed, in this study, to show whether STRN interacts with LCC and PP2A to regulate cardiomyocyte contractility. Herein we report that both protein phosphatase 2A (PP2A) and the LCC were associated with STRN/Cav/CaM complex and that the interaction between all these components was calcium sensitive (abolished by calcium chelator EGTA). In addition, we also show that overexpression of striatin (adenoviral delivery) in cultured cardiomyocytes increased the rate of contraction by ~ 3 fold when compared to control cells (non‐target adenovirus). Preliminary data showed that knockdown of striatin (shRNA targeting STRN) enhanced the interaction of CaM and Caveolin‐3 suggesting a central role for STRN in articulating the STRN/Cav/CaM/LCC/PP2A complex. Collectively, our data suggest that striatin may emerge as a novel regulator of the L‐type calcium channel in cardiomyocytes and consequently regulate their contractility. This work was supported by an operating grant from KFSHRC.