RESUMEN
Accurate methods to assess the pathogenicity of mutations are needed to fully leverage the possibilities of genome sequencing in diagnosis. Current data-driven and bioinformatics approaches are, however, limited by the large number of new variations found in each newly sequenced genome, and often do not provide direct mechanistic insight. Here we demonstrate, for the first time, that saturation mutagenesis, biophysical modeling and co-variation analysis, performed in silico, can predict the abundance, metabolic stability, and function of proteins inside living cells. As a model system, we selected the human mismatch repair protein, MSH2, where missense variants are known to cause the hereditary cancer predisposition disease, known as Lynch syndrome. We show that the majority of disease-causing MSH2 mutations give rise to folding defects and proteasome-dependent degradation rather than inherent loss of function, and accordingly our in silico modeling data accurately identifies disease-causing mutations and outperforms the traditionally used genetic disease predictors. Thus, in conclusion, in silico biophysical modeling should be considered for making genotype-phenotype predictions and for diagnosis of Lynch syndrome, and perhaps other hereditary diseases.
Asunto(s)
Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Proteínas de Unión al ADN/genética , Proteína 2 Homóloga a MutS/genética , Pliegue de Proteína , Neoplasias Colorrectales Hereditarias sin Poliposis/diagnóstico , Neoplasias Colorrectales Hereditarias sin Poliposis/patología , Simulación por Computador , Proteínas de Unión al ADN/química , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Genoma Humano , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Inestabilidad de Microsatélites , Proteína 2 Homóloga a MutS/química , Mutación Missense/genética , Conformación ProteicaRESUMEN
Water mobility in cancer cells could be a powerful parameter to predict the progression or remission of tumors. In the present descriptive work, new insight into this concept was achieved by combining neutron scattering and thermal analyses. The results provide the first step to untangle the role played by water dynamics in breast cancer cells (MCF-7) after treatment with a chemotherapy drug. By thermal analyses, the cells were probed as micrometric reservoirs of bulk-like and confined water populations. Under this perspective we showed that the drug clearly alters the properties of the confined water. We have independently validated this idea by accessing the cellular water dynamics using inelastic neutron scattering. Finally, analysis of the quasi-elastic neutron scattering data allows us to hypothesize that, in this particular cell line, diffusion increases in the intracellular water in response to the action of the drug on the nanosecond timescale.