A Hypertrophic Cardiomyopathy-associated MYBPC3 Mutation Common in Populations of South Asian Descent Causes Contractile Dysfunction
Copyright policy )A Hypertrophic Cardiomyopathy-associated MYBPC3 Mutation Common in Populations of South Asian Descent Causes Contractile Dysfunction
Hypertrophic cardiomyopathy (HCM) results from mutations in genes encoding sarcomeric proteins, most often MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C). A recently discovered HCM-associated 25-base pair deletion in MYBPC3 is inherited in millions worldwide. Although this mutation causes changes in the C10 domain of cMyBP-C (cMyBP-C(C10mut)), which binds to the light meromyosin (LMM) region of the myosin heavy chain, the underlying molecular mechanism causing HCM is unknown. In this study, adenoviral expression of cMyBP-C(C10mut) in cultured adult rat cardiomyocytes was used to investigate protein localization and evaluate contractile function and Ca(2+) transients, compared with wild-type cMyBP-C expression (cMyBP-C(WT)) and controls. Forty-eight hours after infection, 44% of cMyBP-C(WT) and 36% of cMyBP-C(C10mut) protein levels were determined in total lysates, confirming equal expression. Immunofluorescence experiments showed little or no localization of cMyBP-C(C10mut) to the C-zone, whereas cMyBP-C(WT) mostly showed C-zone staining, suggesting that cMyBP-C(C10mut) could not properly integrate in the C-zone of the sarcomere. Subcellular fractionation confirmed that most cMyBP-C(C10mut) resided in the soluble fraction, with reduced presence in the myofilament fraction. Also, cMyBP-C(C10mut) displayed significantly reduced fractional shortening, sarcomere shortening, and relaxation velocities, apparently caused by defects in sarcomere function, because Ca(2+) transients were unaffected. Co-sedimentation and protein cross-linking assays confirmed that C10(mut) causes the loss of C10 domain interaction with myosin LMM. Protein homology modeling studies showed significant structural perturbation in cMyBP-C(C10mut), providing a potential structural basis for the alteration in its mode of interaction with myosin LMM. Therefore, expression of cMyBP-C(C10mut) protein is sufficient to cause contractile dysfunction in vitro.
- Amsterdam UMC, location VUmc Netherlands
- Amsterdam UMC Netherlands
- Miami University United States
- Amsterdam University Medical Centers Netherlands
- Loyola University Chicago United States
Male, Models, Molecular, Asia, Immunoblotting, Rats, Sprague-Dawley, Asian People, Animals, Humans, Genetic Predisposition to Disease, Myocytes, Cardiac, Cells, Cultured, Cell Size, Myosin Subfragments, Cardiomyopathy, Hypertrophic, Protein Structure, Tertiary, Microscopy, Fluorescence, Mutation, Carrier Proteins, Muscle Contraction, Protein Binding
Male, Models, Molecular, Asia, Immunoblotting, Rats, Sprague-Dawley, Asian People, Animals, Humans, Genetic Predisposition to Disease, Myocytes, Cardiac, Cells, Cultured, Cell Size, Myosin Subfragments, Cardiomyopathy, Hypertrophic, Protein Structure, Tertiary, Microscopy, Fluorescence, Mutation, Carrier Proteins, Muscle Contraction, Protein Binding
selected citations These citations are derived from selected sources.This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).21 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Average impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
Citations provided by BIP!Popularity provided by BIP!