RESUMEN
Mutations in the valosin-containing protein (VCP, p97) gene on chromosome 9p13-p12 cause a late-onset form of autosomal dominant inclusion body myopathy associated with Paget disease of the bone and frontotemporal dementia (IBMPFD). We report on the pathological consequences of three heterozygous VCP (R93C, R155H, R155C) mutations on human striated muscle. IBMPFD skeletal muscle pathology is characterized by degenerative changes and filamentous VCP- and ubiquitin-positive cytoplasmic and nuclear protein aggregates. Furthermore, this is the first report demonstrating that mutant VCP leads to a novel form of dilatative cardiomyopathy with inclusion bodies. In contrast to post-mitotic striated muscle cells and neurons of IBMPFD patients, evidence of protein aggregate pathology was not detected in primary IBMPFD myoblasts or in transient and stable transfected cells using wild-type-VCP and R93C-, R155H-, R155C-VCP mutants. Glutathione S-transferase pull-down experiments showed that all three VCP mutations do not affect the binding to Ufd1, Npl4 and ataxin-3. Structural analysis demonstrated that R93 and R155 are both surface-accessible residues located in the centre of cavities that may enable ligand-binding. Mutations at R93 and R155 are predicted to induce changes in the tertiary structure of the VCP protein. The search for putative ligands to the R93 and R155 cavities resulted in the identification of cyclic sugar compounds with high binding scores. The latter findings provide a novel link to VCP carbohydrate interactions in the complex pathology of IBMPFD.
Asunto(s)
Cardiomiopatía Dilatada/genética , Proteínas de Ciclo Celular/genética , Músculo Esquelético/ultraestructura , Mutación , Miositis por Cuerpos de Inclusión/genética , Adenosina Trifosfatasas , Anciano , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/patología , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Cromosomas Humanos Par 9/genética , Análisis Mutacional de ADN/métodos , Bases de Datos Genéticas , Femenino , Humanos , Ligandos , Masculino , Microscopía Confocal , Persona de Mediana Edad , Músculo Esquelético/metabolismo , Mioblastos/patología , Miositis por Cuerpos de Inclusión/metabolismo , Miositis por Cuerpos de Inclusión/patología , Osteítis Deformante/genética , Osteítis Deformante/patología , Fenotipo , Unión Proteica , Estructura Terciaria de Proteína , Enfermedades de la Columna Vertebral/genética , Enfermedades de la Columna Vertebral/patología , Transducción Genética , Transfección , Proteína que Contiene ValosinaRESUMEN
Increased awareness of human papillomavirus (HPV) as an etiological cause of head and neck squamous cell carcinoma has increased the interest in analysis of distinct oral sub-sites. It is currently under debate, whether HPV plays a role in the development of squamous cell carcinoma of the oral cavity (OSCC). The weakness in most published studies is the lack of performing different HPV detection tests combined with analysis for biological activity of the virus. In addition, different sub-sites of the oral cavity had been combined to a single entity, which retrospectively leads to a highly heterogeneous basis of data. In this review we mainly discuss the unclear role of HPV in OSCC development.