Delineating the HMGB1 and HMGB2 interactome in prostate and ovary epithelial cells and its relationship with cancer.

High Mobility Group B (HMGB) proteins are involved in cancer progression and in cellular responses to platinum compounds used in the chemotherapy of prostate and ovary cancer. Here we use affinity purification coupled to mass spectrometry (MS) and yeast two-hybrid (Y2H) screening to carry out an exhaustive study of HMGB1 and HMGB2 protein interactions in the context of prostate and ovary epithelia. We present a proteomic study of HMGB1 partners based on immunoprecipitation of HMGB1 from a non-cancerous prostate epithelial cell line. In addition, HMGB1 and HMGB2 were used as baits in yeast two-hybrid screening of libraries from prostate and ovary epithelial cell lines as well as from healthy ovary tissue. HMGB1 interacts with many nuclear proteins that control gene expression, but also with proteins that form part of the cytoskeleton, cell-adhesion structures and others involved in intracellular protein translocation, cellular migration, secretion, apoptosis and cell survival. HMGB2 interacts with proteins involved in apoptosis, cell motility and cellular proliferation. High confidence interactors, based on repeated identification in different cell types or in both MS and Y2H approaches, are discussed in relation to cancer. This study represents a useful resource for detailed investigation of the role of HMGB1 in cancer of epithelial origins, as well as potential alternative avenues of therapeutic intervention

Characterization of an Autoinducer of Penicillin Biosynthesis in Penicillium chrysogenum▿†

Filamentous fungi produce an impressive variety of secondary metabolites; many of them have important biological activities. The biosynthesis of these secondary metabolites is frequently induced by plant-derived external elicitors and appears to also be regulated by internal inducers, which may work in a way similar to that of bacterial autoinducers. The biosynthesis of penicillin in Penicillium chrysogenum is an excellent model for studying the molecular mechanisms of control of gene expression due to a good knowledge of the biochemistry and molecular genetics of β-lactam antibiotics and to the availability of its genome sequence and proteome. In this work, we first developed a plate bioassay that allows direct testing of inducers of penicillin biosynthesis using single colonies of P. chrysogenum. Using this bioassay, we have found an inducer substance in the conditioned culture broths of P. chrysogenum and Acremonium chrysogenum. No inducing effect was exerted by γ-butyrolactones, jasmonic acid, or the penicillin precursor δ-(l-α-aminoadipyl)-l-cysteinyl-d-valine. The conditioned broth induced penicillin biosynthesis and transcription of the pcbAB, pcbC, and penDE genes when added at inoculation time, but its effect was smaller if added at 12 h and it had no effect when added at 24 h, as shown by Northern analysis and lacZ reporter studies. The inducer molecule was purified and identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR) as 1,3-diaminopropane. Addition of pure 1,3-diaminopropane stimulated the production of penicillin by about 100% compared to results for the control cultures. Genes for the biosynthesis of 1,3-diaminopropane have been identified in the P. chrysogenum genome