Project description:To address the molecular mechanisms underlying c-Src-induced cell transformation, we previously developed a model system using Csk-deficient fibroblasts that can be transformed by wild-type c-Src. In this study, we applied this system for the analysis of the potential contribution of mRNA and miRNA to c-Src-induced cell transformation. We found miR-129-3p was downregulated in c-Src-induced cell transformation in a Dox-inducible expression system via c-Src, c-Yes, and Fer.
Project description:To address the molecular mechanisms underlying c-Src-induced cell transformation, we previously developed a model system using Csk-deficient fibroblasts that can be transformed by wild-type c-Src. In this study, we applied this system for the analysis of the potential contribution of mRNA and miRNA to c-Src-induced cell transformation. We found miR-129-3p was downregulated in c-Src-induced cell transformation in a Dox-inducible expression system via c-Src, c-Yes, and Fer.
Project description:Primary cilium serves as a cellular “antenna” to sense environmental signals. Ciliogenesis requires the removal of CP110 to convert the mother centriole into the basal body. Actin dynamics is also critical for cilia formation. How these distinct processes are properly regulated remains unknown. Here we show that miR-129-3p, a microRNA conserved in the vertebrates, controlled cilia assembly by down-regulating both CP110 and four proteins critical for actin dynamics, Arp2, Toca1, abLIM1, and abLIM3. Consistently, blocking miR-129-3p repressed cilia formation in cultured mammalian cells, whereas its overexpression potently induced ciliogenesis in proliferating cells and extraordinary cilia elongation. Moreover, inhibition of miR-129-3p in zebrafish embryos suppressed cilia assembly in the Kupffer’s vesicle and pronephric duct, leading to developmental abnormalities including curved body, pericardial oedema, and randomised left-right patterning. Our results thus unravel a novel mechanism that orchestrates both the centriole-to-basal body transition and subsequent cilia assembly via microRNA-mediated posttranscriptional regulations. We want to find the targets of miR-129-3p by overexpressing miR-129-3p oligo or control oligo in hTERT-RPE1 cells. Through microarray analysis we could check the downregulated genes and these genes might be the targets of miR-129-3p.
Project description:Primary cilium serves as a cellular M-bM-^@M-^\antennaM-bM-^@M-^] to sense environmental signals. Ciliogenesis requires the removal of CP110 to convert the mother centriole into the basal body. Actin dynamics is also critical for cilia formation. How these distinct processes are properly regulated remains unknown. Here we show that miR-129-3p, a microRNA conserved in the vertebrates, controlled cilia assembly by down-regulating both CP110 and four proteins critical for actin dynamics, Arp2, Toca1, abLIM1, and abLIM3. Consistently, blocking miR-129-3p repressed cilia formation in cultured mammalian cells, whereas its overexpression potently induced ciliogenesis in proliferating cells and extraordinary cilia elongation. Moreover, inhibition of miR-129-3p in zebrafish embryos suppressed cilia assembly in the KupfferM-bM-^@M-^Ys vesicle and pronephric duct, leading to developmental abnormalities including curved body, pericardial oedema, and randomised left-right patterning. Our results thus unravel a novel mechanism that orchestrates both the centriole-to-basal body transition and subsequent cilia assembly via microRNA-mediated posttranscriptional regulations. We want to find the targets of miR-129-3p by overexpressing miR-129-3p oligo or control oligo in hTERT-RPE1 cells. Through microarray analysis we could check the downregulated genes and these genes might be the targets of miR-129-3p. RPE1 cells were transfected with control (Ctrl) or miR-129-3p (M129) oligo for 72h, and harvested for RNA extraction and hybridization on Affymetrix microarrays. Two samples: RPE1-Ctrl, RPE1-M129
Project description:The membrane anchored Src tyrosine kinase is involved in numerous pathways and its deregulation is involved in human cancer. Our knowledge on Src regulation relies on crystallography, which revealed intramolecular interactions to control active Src conformations. However, Src contains a N-terminal intrinsically disordered unique domain (UD) whose function remains unclear. Using NMR, we reported that UD forms an intramolecular fuzzy complex involving a conserved region with lipid-binding capacity named Unique Lipid Binding Region (ULBR), which could modulate Src membrane anchoring. Here we show that the ULBR is essential for Src’s oncogenic capacity. ULBR inactive mutations inhibited Src transforming activity in NIH3T3 cells and in human colon cancer cells. It also reduced Src-induced tumor development in nude mice. An intact ULBR was required for MAPK signaling without affecting Src kinase activity nor sub-cellular localization. Phospho-proteomic analyses revealed that, while not impacting on the global tyrosine phospho-proteome in colon cancer cells, this region modulates phosphorylation of specific membrane-localized tyrosine kinases needed for Src oncogenic signaling, including EPHA2 and Fyn. Collectively, this study reveals an important role of this intrinsically disordered region in malignant cell transformation and suggests a novel layer of Src regulation by this unique region via membrane substrate phosphorylation.
Project description:Farnesoid-X-Receptor (FXR) plays a central role in maintaining bile acid (BA) homeostasis by transcriptional control of numerous enterohepatic genes, including intestinal FGF19, a hormone that strongly represses hepatic BA synthesis. How activation of the FGF19 receptor at the membrane is transmitted to the nucleus for transcriptional regulation of BA levels and whether FGF19 signaling posttranslationally modulates function of FXR remain largely unknown. Here we show that FXR is phosphorylated at Y67 by non-receptor tyrosine kinase, Src, in response to postprandial FGF19, which is critical for its nuclear localization and transcriptional regulation of BA levels. Liver-specific expression of phospho-defective Y67F-FXR or Src-downregulation in mice result in impaired homeostatic responses to acute BA feeding, and exacerbate cholestatic pathologies upon drug-induced hepatobiliary insults. Also, the hepatic FGF19-Src-FXR pathway is defective in primary biliary cirrhosis patients. This study identifies Src-mediated FXR phosphorylation as a potential therapeutic target and biomarker for BA-related enterohepatic diseases.
Project description:Nontransformed cells form heterotypic cadherin junctions with adjacent transformed cells to inhibit tumor cell growth and motility. Transformed cells must override this form of growth control, called contact normalization, to invade and metastasize during cancer progression. Heterocellular cadherin junctions between transformed and nontransformed cells are needed for this process. However, specific mechanisms downstream of cadherin signaling have not been clearly elucidated. Here, we utilized a b-catenin reporter construct to determine if contact normalization affects Wnt signaling in transformed cells. b-catenin driven GFP expression in Src transformed mouse embryonic cells was decreased when cultured with cadherin competent nontransformed cells compared to transformed cells cultured with themselves, but not when cultured with cadherin deficient nontransformed cells. We also utilized a layered culture system to investigate the effects of oncogenic transformation and contact normalization on gene expression and oncogenic Src kinase mediated phosphorylation events. RNA-Seq analysis found that the cadherin dependent contact normalization inhibited the expression of 22 transcripts that were induced by Src transformation, and increased the expression of 78 transcripts that were suppressed by Src transformation. Phosphoproteomic analysis of cells expressing a temperature sensitive Src kinase construct found that contact normalization decreased phosphorylation of 10 proteins on tyrosine residues that were phosphorylated within 1 hour of Src kinase activation in transformed cells. Taken together, these results indicate that cadherin dependent contact normalization inhibits Wnt signaling to regulate oncogenic kinase activity and gene expression, particularly PDPN expression, in transformed cells in order to control tumor progression.