RESUMEN
The heterotrimeric G-protein complex is minimally composed of Gα, Gß, and Gγ subunits. In the classic scenario, the G-protein complex is the nexus in signaling from the plasma membrane, where the heterotrimeric G-protein associates with heptahelical G-protein-coupled receptors (GPCRs), to cytoplasmic target proteins called effectors. Although a number of effectors are known in metazoans and fungi, none of these are predicted to exist in their canonical forms in plants. To identify ab initio plant G-protein effectors and scaffold proteins, we screened a set of proteins from the G-protein complex using two-hybrid complementation in yeast. After deep and exhaustive interrogation, we detected 544 interactions between 434 proteins, of which 68 highly interconnected proteins form the core G-protein interactome. Within this core, over half of the interactions comprising two-thirds of the nodes were retested and validated as genuine in planta. Co-expression analysis in combination with phenotyping of loss-of-function mutations in a set of core interactome genes revealed a novel role for G-proteins in regulating cell wall modification.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis , Pared Celular , Proteínas de Unión al GTP/metabolismo , Glicómica , Proteómica , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/genética , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Membrana Celular/genética , Membrana Celular/metabolismo , Pared Celular/genética , Pared Celular/metabolismo , Bases de Datos Genéticas , Proteínas de Unión al GTP/genética , Regulación de la Expresión Génica de las Plantas , Redes Reguladoras de Genes , Prueba de Complementación Genética , Genotipo , Inmunoprecipitación , Morfogénesis/genética , Fenotipo , Mapeo de Interacción de Proteínas , Receptores Acoplados a Proteínas G/genética , Técnicas del Sistema de Dos HíbridosRESUMEN
A key principle of oncolytic viral therapy is that many cancers develop defects in their antiviral responses, making them more susceptible to virus infection. However, some cancers display resistance to viral infection. Many of these resistant cancers constitutively express interferon-stimulated genes (ISGs). The goal of these experiments was to determine the role of two tumor suppressor genes, MAP3K7 and CHD1, in viral resistance and ISG expression in PC3 prostate cancer cells resistant to oncolytic vesicular stomatitis virus (VSV). MAP3K7 and CHD1 are often co-deleted in aggressive prostate cancers. Silencing expression of MAP3K7 and CHD1 in PC3 cells increased susceptibility to the matrix (M) gene mutant M51R-VSV, as shown by increased expression of viral genes, increased yield of progeny virus, and reduction of tumor growth in nude mice. Silencing MAP3K7 alone had a greater effect on virus susceptibility than did silencing CHD1. Silencing MAP3K7 and CHD1 decreased constitutive expression of ISG mRNAs and proteins, whereas silencing MAP3K7 alone decreased expression of ISG proteins, but actually increased expression of ISG mRNAs. These results suggest a role for the protein product of MAP3K7, transforming growth factor ß-activated kinase 1 (TAK1), in regulating translation of ISG mRNAs and a role of CHD1 in maintaining the transcription of ISGs.