Cardiomyopathy Mutations in Metavinculin Disrupt Regulation of Vinculin-Induced F-Actin Assemblies

Muzaddid Sarker, Hyunna T. Lee, Lin Mei, Andrey Krokhotin, Santiago Espinosa de los Reyes, Laura Yen, Lindsey M. Costantini, Jack Griffith, Nikolay Dokholyan, Gregory M. Alushin, Sharon L. Campbell

Research output: Contribution to journalArticle

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Abstract

Debilitating heart conditions, notably dilated and hypertrophic cardiomyopathies (CMs), are associated with point mutations in metavinculin, a larger isoform of the essential cytoskeletal protein vinculin. Metavinculin is co-expressed with vinculin at sub-stoichiometric ratios in cardiac tissues. CM mutations in the metavinculin tail domain (MVt) occur within the extra 68-residue insert that differentiates it from the vinculin tail domain (Vt). Vt binds actin filaments (F-actin) and promotes vinculin dimerization to bundle F-actin into thick fibers. While MVt binds to F-actin in a similar manner to Vt, MVt is incapable of F-actin bundling and inhibits Vt-mediated F-actin bundling. We performed F-actin co-sedimentation and negative-stain EM experiments to dissect the coordinated roles of metavinculin and vinculin in actin fiber assembly and the effects of three known metavinculin CM mutations. These CM mutants were found to weakly induce the formation of disordered F-actin assemblies. Notably, they fail to inhibit Vt-mediated F-actin bundling and instead promote formation of large assemblies embedded with linear bundles. Computational models of MVt bound to F-actin suggest that MVt undergoes a conformational change licensing the formation of a protruding sub-domain incorporating the insert, which sterically prevents dimerization and bundling of F-actin by Vt. Sub-domain formation is destabilized by CM mutations, disrupting this inhibitory mechanism. These findings provide new mechanistic insights into the ability of metavinculin to tune actin organization by vinculin and suggest that dysregulation of this process by CM mutants could underlie their malfunction in disease.

Original languageEnglish (US)
Pages (from-to)1604-1618
Number of pages15
JournalJournal of Molecular Biology
Volume431
Issue number8
DOIs
StatePublished - Apr 5 2019

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Vinculin
Cardiomyopathies
Actins
Mutation
Dimerization
metavinculin
Cytoskeletal Proteins
Hypertrophic Cardiomyopathy
Dilated Cardiomyopathy
Licensure
Actin Cytoskeleton
Point Mutation
Protein Isoforms

All Science Journal Classification (ASJC) codes

  • Molecular Biology

Cite this

Sarker, M., Lee, H. T., Mei, L., Krokhotin, A., de los Reyes, S. E., Yen, L., ... Campbell, S. L. (2019). Cardiomyopathy Mutations in Metavinculin Disrupt Regulation of Vinculin-Induced F-Actin Assemblies. Journal of Molecular Biology, 431(8), 1604-1618. https://doi.org/10.1016/j.jmb.2019.02.024
Sarker, Muzaddid ; Lee, Hyunna T. ; Mei, Lin ; Krokhotin, Andrey ; de los Reyes, Santiago Espinosa ; Yen, Laura ; Costantini, Lindsey M. ; Griffith, Jack ; Dokholyan, Nikolay ; Alushin, Gregory M. ; Campbell, Sharon L. / Cardiomyopathy Mutations in Metavinculin Disrupt Regulation of Vinculin-Induced F-Actin Assemblies. In: Journal of Molecular Biology. 2019 ; Vol. 431, No. 8. pp. 1604-1618.
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abstract = "Debilitating heart conditions, notably dilated and hypertrophic cardiomyopathies (CMs), are associated with point mutations in metavinculin, a larger isoform of the essential cytoskeletal protein vinculin. Metavinculin is co-expressed with vinculin at sub-stoichiometric ratios in cardiac tissues. CM mutations in the metavinculin tail domain (MVt) occur within the extra 68-residue insert that differentiates it from the vinculin tail domain (Vt). Vt binds actin filaments (F-actin) and promotes vinculin dimerization to bundle F-actin into thick fibers. While MVt binds to F-actin in a similar manner to Vt, MVt is incapable of F-actin bundling and inhibits Vt-mediated F-actin bundling. We performed F-actin co-sedimentation and negative-stain EM experiments to dissect the coordinated roles of metavinculin and vinculin in actin fiber assembly and the effects of three known metavinculin CM mutations. These CM mutants were found to weakly induce the formation of disordered F-actin assemblies. Notably, they fail to inhibit Vt-mediated F-actin bundling and instead promote formation of large assemblies embedded with linear bundles. Computational models of MVt bound to F-actin suggest that MVt undergoes a conformational change licensing the formation of a protruding sub-domain incorporating the insert, which sterically prevents dimerization and bundling of F-actin by Vt. Sub-domain formation is destabilized by CM mutations, disrupting this inhibitory mechanism. These findings provide new mechanistic insights into the ability of metavinculin to tune actin organization by vinculin and suggest that dysregulation of this process by CM mutants could underlie their malfunction in disease.",
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Sarker, M, Lee, HT, Mei, L, Krokhotin, A, de los Reyes, SE, Yen, L, Costantini, LM, Griffith, J, Dokholyan, N, Alushin, GM & Campbell, SL 2019, 'Cardiomyopathy Mutations in Metavinculin Disrupt Regulation of Vinculin-Induced F-Actin Assemblies', Journal of Molecular Biology, vol. 431, no. 8, pp. 1604-1618. https://doi.org/10.1016/j.jmb.2019.02.024

Cardiomyopathy Mutations in Metavinculin Disrupt Regulation of Vinculin-Induced F-Actin Assemblies. / Sarker, Muzaddid; Lee, Hyunna T.; Mei, Lin; Krokhotin, Andrey; de los Reyes, Santiago Espinosa; Yen, Laura; Costantini, Lindsey M.; Griffith, Jack; Dokholyan, Nikolay; Alushin, Gregory M.; Campbell, Sharon L.

In: Journal of Molecular Biology, Vol. 431, No. 8, 05.04.2019, p. 1604-1618.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cardiomyopathy Mutations in Metavinculin Disrupt Regulation of Vinculin-Induced F-Actin Assemblies

AU - Sarker, Muzaddid

AU - Lee, Hyunna T.

AU - Mei, Lin

AU - Krokhotin, Andrey

AU - de los Reyes, Santiago Espinosa

AU - Yen, Laura

AU - Costantini, Lindsey M.

AU - Griffith, Jack

AU - Dokholyan, Nikolay

AU - Alushin, Gregory M.

AU - Campbell, Sharon L.

PY - 2019/4/5

Y1 - 2019/4/5

N2 - Debilitating heart conditions, notably dilated and hypertrophic cardiomyopathies (CMs), are associated with point mutations in metavinculin, a larger isoform of the essential cytoskeletal protein vinculin. Metavinculin is co-expressed with vinculin at sub-stoichiometric ratios in cardiac tissues. CM mutations in the metavinculin tail domain (MVt) occur within the extra 68-residue insert that differentiates it from the vinculin tail domain (Vt). Vt binds actin filaments (F-actin) and promotes vinculin dimerization to bundle F-actin into thick fibers. While MVt binds to F-actin in a similar manner to Vt, MVt is incapable of F-actin bundling and inhibits Vt-mediated F-actin bundling. We performed F-actin co-sedimentation and negative-stain EM experiments to dissect the coordinated roles of metavinculin and vinculin in actin fiber assembly and the effects of three known metavinculin CM mutations. These CM mutants were found to weakly induce the formation of disordered F-actin assemblies. Notably, they fail to inhibit Vt-mediated F-actin bundling and instead promote formation of large assemblies embedded with linear bundles. Computational models of MVt bound to F-actin suggest that MVt undergoes a conformational change licensing the formation of a protruding sub-domain incorporating the insert, which sterically prevents dimerization and bundling of F-actin by Vt. Sub-domain formation is destabilized by CM mutations, disrupting this inhibitory mechanism. These findings provide new mechanistic insights into the ability of metavinculin to tune actin organization by vinculin and suggest that dysregulation of this process by CM mutants could underlie their malfunction in disease.

AB - Debilitating heart conditions, notably dilated and hypertrophic cardiomyopathies (CMs), are associated with point mutations in metavinculin, a larger isoform of the essential cytoskeletal protein vinculin. Metavinculin is co-expressed with vinculin at sub-stoichiometric ratios in cardiac tissues. CM mutations in the metavinculin tail domain (MVt) occur within the extra 68-residue insert that differentiates it from the vinculin tail domain (Vt). Vt binds actin filaments (F-actin) and promotes vinculin dimerization to bundle F-actin into thick fibers. While MVt binds to F-actin in a similar manner to Vt, MVt is incapable of F-actin bundling and inhibits Vt-mediated F-actin bundling. We performed F-actin co-sedimentation and negative-stain EM experiments to dissect the coordinated roles of metavinculin and vinculin in actin fiber assembly and the effects of three known metavinculin CM mutations. These CM mutants were found to weakly induce the formation of disordered F-actin assemblies. Notably, they fail to inhibit Vt-mediated F-actin bundling and instead promote formation of large assemblies embedded with linear bundles. Computational models of MVt bound to F-actin suggest that MVt undergoes a conformational change licensing the formation of a protruding sub-domain incorporating the insert, which sterically prevents dimerization and bundling of F-actin by Vt. Sub-domain formation is destabilized by CM mutations, disrupting this inhibitory mechanism. These findings provide new mechanistic insights into the ability of metavinculin to tune actin organization by vinculin and suggest that dysregulation of this process by CM mutants could underlie their malfunction in disease.

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