RESUMEN
The LIM and SH3 domain protein 1 (Lasp1) was originally cloned from metastatic breast cancer and characterised as an adaptor molecule associated with tumourigenesis and cancer cell invasion. However, the regulation of Lasp1 and its function in the aggressive transformation of cells is unclear. Here we use integrative epigenomic profiling of invasive fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) and from mouse models of the disease, to identify Lasp1 as an epigenomically co-modified region in chronic inflammatory arthritis and a functionally important binding partner of the Cadherin-11/ß-Catenin complex in zipper-like cell-to-cell contacts. In vitro, loss or blocking of Lasp1 alters pathological tissue formation, migratory behaviour and platelet-derived growth factor response of arthritic FLS. In arthritic human TNF transgenic mice, deletion of Lasp1 reduces arthritic joint destruction. Therefore, we show a function of Lasp1 in cellular junction formation and inflammatory tissue remodelling and identify Lasp1 as a potential target for treating inflammatory joint disorders associated with aggressive cellular transformation.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Uniones Adherentes/metabolismo , Artritis/metabolismo , Transformación Celular Neoplásica/metabolismo , Proteínas del Citoesqueleto/metabolismo , Fibroblastos/metabolismo , Proteínas con Dominio LIM/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Artritis/patología , Artritis Reumatoide/metabolismo , Artritis Reumatoide/patología , Cadherinas/metabolismo , Proteínas del Citoesqueleto/genética , Femenino , Proteínas de Homeodominio , Proteínas con Dominio LIM/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Osteoblastos , beta Catenina/metabolismoRESUMEN
C15orf2 (Chromosome 15 open reading frame 2) is an intronless gene, which is located in the Prader-Willi syndrome (PWS) chromosomal region on human chromosome 15. Mice do not have an orthologous gene. Here we show that expression of C15orf2 in the fetal human brain is imprinted. Using Western blot and immunohistological studies we have obtained evidence that C15orf2 protein is present in several regions of the brain. Previously published phylogenetic studies as well as population genetic studies based on complex haplotypes as described here suggest that C15orf2 is under positive Darwinian selection. These results indicate that C15orf2 might have an important role in human biology and that a deficiency of C15orf2 might contribute to PWS.
Asunto(s)
Cromosomas Humanos Par 15/genética , Impresión Genómica , Proteínas del Tejido Nervioso/genética , Sistemas de Lectura Abierta , Síndrome de Prader-Willi/genética , Selección Genética , Alelos , Animales , Línea Celular , Haplotipos , Humanos , Hipotálamo/citología , Hipotálamo/metabolismo , Ratones , Proteínas del Tejido Nervioso/metabolismo , Proteínas de Complejo Poro Nuclear , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
The TRPS1 gene encodes a repressor of GATA-mediated transcription. Mutations in this gene cause the tricho-rhino-phalangeal syndromes, but the affected pathways are unknown. In a yeast two-hybrid screen with the C-terminal part of the murine Trps1 protein as bait, we obtained three yeast clones encoding two overlapping fragments of the 194 amino acids RING finger protein 4 (Rnf4). The overlap narrows down the Trps1-binding region within Rnf4 to amino acids 6-65. This region in Rnf4 is also known to interact with several proteins including steroid receptors. By using truncated Trps1 constructs, the Rnf4-binding region in Trps1 could be assigned to amino acids 985-1184 of 1281. This 200 amino acid region of Trps1 does not contain any predicted protein-protein interacting motif. Complex formation between the human proteins TRPS1 and RNF4 was verified by co-immunoprecipitation from transfected and native mammalian cells. Confocal laser-scanning microscopy revealed that the endogenous proteins are located in distinct structures of the nucleus. Using a luciferase reporter assay, we could demonstrate that the repressional function of TRPS1 is inhibited by RNF4. This finding suggests that RNF4 is a negative regulator of TRPS1 activity.