Key result
Lys328 pseudoacetylation of actin significantly enhanced the Ca2+ sensitivity of reconstituted thin filament activation compared to wild-type control.
Why the study?
Recent proteomics studies identified lysine acetylation on actin, including Lys326 and Lys328, but its residue-specific consequences on troponin-tropomyosin-based actomyosin regulation were unknown.
Population
Reconstituted thin filaments and F-actin
Comparison
Chemically acetylated or K326Q and K328Q acetyl-mimetic actin vs control
Design
In vitro experimental study
Authors
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Actin acetylation may modulate tropomyosin positioning in striated muscle; leaves open its relevance to cardiac thin-filament regulation.
Absolute Event Rate: 0.56% vs 0.87%
p-value: p=<0.0001
Actin acetylation, particularly at Lys328, reduces tropomyosin-mediated inhibition of actomyosin binding, thereby enhancing the calcium sensitivity of muscle contraction.
Schmidt et al. (2020) studied this question. Lysine acetylation of F-actin (Lys328 pseudoacetylation) vs. Wild-type (unacetylated) F-actin was evaluated on Ca2+ sensitivity of reconstituted thin filaments activation ([Ca2+]50 in μM) (p=<0.0001). Lys328 pseudoacetylation of actin significantly enhanced the Ca2+ sensitivity of reconstituted thin filament activation compared to wild-type control.
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