RESUMEN
The Biomolecular Interaction Network Database (BIND) (http://bind.ca) archives biomolecular interaction, reaction, complex and pathway information. Our aim is to curate the details about molecular interactions that arise from published experimental research and to provide this information, as well as tools to enable data analysis, freely to researchers worldwide. BIND data are curated into a comprehensive machine-readable archive of computable information and provides users with methods to discover interactions and molecular mechanisms. BIND has worked to develop new methods for visualization that amplify the underlying annotation of genes and proteins to facilitate the study of molecular interaction networks. BIND has maintained an open database policy since its inception in 1999. Data growth has proceeded at a tremendous rate, approaching over 100 000 records. New services provided include a new BIND Query and Submission interface, a Standard Object Access Protocol service and the Small Molecule Interaction Database (http://smid.blueprint.org) that allows users to determine probable small molecule binding sites of new sequences and examine conserved binding residues.
Asunto(s)
Biopolímeros/química , Bases de Datos Factuales , Programas Informáticos , Animales , Sitios de Unión , Bovinos , Gráficos por Computador , Humanos , Internet , Ratones , Interfaz Usuario-ComputadorRESUMEN
MAD-related (MADR) proteins are essential intracellular components of TGFbeta signaling pathways and are regulated by phosphorylation. Here, we demonstrate that MADR2 and not the related protein DPC4 transiently interacts with the TGFbeta receptor and is directly phosphorylated by the complex on C-terminal serines. Interaction of MADR2 with receptors and phosphorylation requires activation of receptor I by receptor II and is mediated by the receptor I kinase. Mutation of the phosphorylation sites generates a dominant negative MADR2 that blocks TGFbeta-dependent transcriptional responses, stably associates with receptors, and fails to accumulate in the nucleus in response to TGFbeta signaling. Thus, transient association and phosphorylation of MADR2 by the TGFbeta receptor is necessary for nuclear accumulation and initiation of signaling.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Transactivadores , Animales , Compartimento Celular , Núcleo Celular/metabolismo , Células Cultivadas , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Sustancias Macromoleculares , Ratones , Proteínas Nucleares/metabolismo , Fosforilación , Fosfoserina/metabolismo , Transducción de Señal , Proteína Smad2RESUMEN
The MAD-related (MADR) family of proteins are essential components in the signaling pathways of serine/threonine kinase receptors for the transforming growth factor beta (TGFbeta) superfamily. We demonstrate that MADR2 is specifically regulated by TGFbeta and not bone morphogenetic proteins. The gene for MADR2 was found to reside on chromosome 18q21, near DPC4, another MADR protein implicated in pancreatic cancer. Mutational analysis of MADR2 in sporadic tumors identified four missense mutations in colorectal carcinomas, two of which display a loss of heterozygosity. Biochemical and functional analysis of three of these demonstrates that the mutations are inactivating. These findings suggest that MADR2 is a tumor suppressor and that mutations acquired in colorectal carcinomas may function to disrupt TGFbeta signaling.
Asunto(s)
Cromosomas Humanos Par 18 , Neoplasias Colorrectales/genética , Proteínas de Unión al ADN/genética , Genes Supresores de Tumor , Fosfoproteínas/genética , Transactivadores , Factor de Crecimiento Transformador beta/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , ADN Complementario/genética , Humanos , Datos de Secuencia Molecular , Sondas de Oligonucleótidos/química , Fosforilación , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Transducción de Señal , Proteína Smad2 , Relación Estructura-Actividad , Proteínas de Xenopus , Xenopus laevisRESUMEN
Thiosulfate is a naturally occurring product of sulfur metabolism. Assays of urinary thiosulfate have been based on the reaction with cyanide to form thiocyanate. However, matrix interferences and background variation in endogenous thiocyanate excretion place serious constraints on this method for determination of physiological amounts of thiosulfate in urine. We describe a column-switching ion chromatographic separation for urinary thiosulfate that allows for sensitive and accurate detection by ion conductimetry. In 20 adult volunteers, we found a lower urinary thiosulfate (8.50 +/- 7.39 mumol/24 h, mean +/- S.D.) than others have described, although the upward skew of the results (median, 6.90; range, 0.84-32 mumol/24 h) was similar. However, we have not observed any of the interferences and the sensitivity of our technique (< 0.2 mumol/24 h) allows for detection of thiosulfate in all control samples. This sort of methodological improvement will be essential for any study of physiological thiosulfate metabolism.