title: Disease-associated mutations in the coil 2B domain of human lamin A/C affect structural properties that mediate dimerization and intermediate filament formation.
abstract: The lamin proteins are essential components of the nuclear lamina of eukaryotic cells, that are involved in a complex association mechanism to attain a functional supermolecular structure. Mutations of the lamin A/C gene are associated with several different neuromuscular diseases, and the detailed effect of disease-associated amino acid substitutions on the structure and stability of human lamin dimers is yet unknown. Here we present a structural and thermodynamic characterization by means of molecular dynamics simulations of the effect of pathological mutations (S326T, R331P, R331Q, E347K, E358K, M371K, and R377H) on the association of the coil 2B domains that mediate lamin A/C oligomerization. The structures attained during the simulations, along with the quantification of the contribution of each residue to the dimerization energies, support a lamin association mechanism mediated by homophilic intermolecular interactions promoted by dissociative conformational changes at distinct positions in the coiled coil. The pathogenic mutations can both increase or decrease the stability of lamin A/C dimers, and a possible correlation between the effect of the amino acid substitutions and disease onset and severity is presented.
authors.affiliation: Biocrystallography Unit, Department of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milano, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Gangemi
authors.forename: Massimo
authors.initials: M
authors.lastname: Degano
mesh_terms: D006801:Humans; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007382:Intermediate Filaments; D034904:Lamin Type A / Q000737:chemistry* / Q000235:genetics; D056004:Molecular Dynamics Simulation; D020125:Mutation, Missense; D009468:Neuromuscular Diseases / Q000235:genetics*; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013816:Thermodynamics
chemical_list: C494847:LMNA protein, human; D034904:Lamin Type A