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Structure‐Function Relationship and Local Subcellular Signaling using Heart Failure Relevant Molecular Defined Muscle Specific mAKAP Mutants
Author(s) -
Rababah Abeer,
Craft John,
Singh Sonal,
Atrooz Fatin,
Wijaya Cori,
McConnell Bradley
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.882.6
Subject(s) - phosphorylation , protein kinase a , mutation , phosphatase , microbiology and biotechnology , biology , mutant , protein phosphatase 2 , signal transduction , ryanodine receptor , protein subunit , receptor , biochemistry , gene
Beta adrenergic stimulation signals through phosphorylation of downstream proteins such as protein kinase A (PKA). PKA substrate phosphorylation is facilitated through its co localization with its signaling partner by A kinase anchoring proteins (AKAPs). Particularly, mAKAP (muscle selective AKAP) localizes PKA and its target substrates such as phosphodiesterase 4D3 (PDE4D3), ryanodine receptor and protein phosphatase (PP2A). We have recently identified potentially important human mAKAP mutations located within or near key protein binding sites critical to beta adrenergic receptor signaling. Three mutations (P1400S, S2195F and L717V) were cloned for the purpose of comparing whether these substitutions disrupted mAKAP binding to the PKA regulatory subunit RIIα or PDE4D3 binding domain and to understand whether these mutations mediated altered signaling. Interestingly, S2195F, a mutation located in PP2A binding site, showed similar protein expression (p=0.3) to wild type mAKAP, but with a significant increase in binding propensity to RIIα after cell stimulation. This result was corroborated by immunopreciptation (p=0.0003). Consequently, PKA activity showed a significant increase with mAKAP S2195F mutation, as compared to wild type. In conclusion, mAKAP S2195F displayed modified activity and binding propensities and may participate in hypertrophy. This work was supported by NIH (HL085487).