• BMB Reports
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• v.56 no.11
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• pp.612-617
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• 2023

Pleiotropic regulator 1 (PLRG1), a highly conserved element in the spliceosome, can form a NineTeen Complex (NTC) with Prp19, SPF27, and CDC5L. This complex plays crucial roles in both pre-mRNA splicing and DNA repair processes. Here, we provide evidence that PLRG1 has a multifaceted impact on cancer cell proliferation. Comparing its expression levels in cancer and normal cells, we observed that PLRG1 was upregulated in various tumor tissues and cell lines. Knockdown of PLRG1 resulted in tumor-specific cell death. Depletion of PLRG1 had notable effects, including mitotic arrest, microtubule instability, endoplasmic reticulum (ER) stress, and accumulation of autophagy, ultimately culminating in apoptosis. Our results also demonstrated that PLRG1 downregulation contributed to DNA damage in cancer cells, which we confirmed through experimental validation as DNA repair impairment. Interestingly, when PLRG1 was decreased in normal cells, it induced G1 arrest as a self-protective mechanism, distinguishing it from effects observed in cancer cells. These results highlight multifaceted impacts of PLRG1 in cancer and underscore its potential as a novel anti-cancer strategy by selectively targeting cancer cells.

• Molecules and Cells
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• v.38 no.1
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• pp.20-25
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• 2015

TGF-${\beta}$ regulates pleiotropic cellular responses including cell growth, differentiation, migration, apoptosis, extracellular matrix production, and many other biological processes. Although non-Smad signaling pathways are being increasingly reported to play many roles in TGF-${\beta}$-mediated biological processes, Smads, especially receptor-regulated Smads (R-Smads), still play a central mediatory role in TGF-${\beta}$ signaling for epithelial-mesenchymal transition. Thus, the biological activities of R-Smads are tightly regulated at multiple points. Inhibitory Smad (I-Smad also called Smad7) acts as a critical endogenous negative feedback regulator of Smad-signaling pathways by inhibiting R-Smad phosphorylation and by inducing activated type I TGF-${\beta}$ receptor degradation. Roles played by Smad7 in health and disease are being increasingly reported, but the molecular mechanisms that regulate Smad7 are not well understood. In this study, we show that E3 ubiquitin ligase Itch acts as a positive regulator of TGF-${\beta}$ signaling and of subsequent EMT-related gene expression. Interestingly, the Itch-mediated positive regulation of TGF-${\beta}$ signaling was found to be dependent on Smad7 ubiquitination and its subsequent degradation. Further study revealed Itch acts as an E3 ubiquitin ligase for Smad7 polyubiquitination, and thus, that Itch is an important regulator of Smad7 activity and a positive regulator of TGF-${\beta}$ signaling and of TGF-${\beta}$-mediated biological processes. Accordingly, the study uncovers a novel regulatory mechanism whereby Smad7 is controlled by Itch.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.39-47
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• 2015

Secondary metabolism in actinomycetes has been known to be controlled by a small molecule, ${\gamma}$-butyrolactone autoregulator, the binding of which to each corresponding receptor leads to the regulation of the transcriptional expression of the secondary metabolites. We expected that expression of an autoregulator receptor or a pleiotropic regulator in a non-host was to be gained insight of effective production of new metabolic materials. In order to study the function of the receptor protein (seaR), which is isolated from Saccharopolyspora erythraea, we introduced the seaR gene to Streptomyces coelicolor A3(2) as host strains. An effective transformation procedure for S. coelicolor A3(2) was established based on transconjugation by Escherichia coli ET12567/pUZ8002 with a ${\varphi}C31$-derived integration vector, pSET152, which contained int, oriT, attP and $ermEp^*$ (erythromycin promotor). Therefore, the pEV615 was introduced into S. coelicolor A3(2) by conjugation and integrated at the attB locus in the chromosome of the recipients by the ${\varphi}C31$ integrase (int) function. Exconjugant of S. coelicolor A3(2) containing the seaR gene was confirmed by PCR and transcriptional expression of the seaR gene in the transformant was analyzed by RT-PCR. In case of S. coelicolor A3(2), a phenotype microarray was used to analyze the phenotype of transformant compared with wild type by seaR expression. After that, in order to confirm the accuracy of the results obtained from the phenotype microarray, an antimicrobial susceptibility test was carried out. This test indicated that sensitivity of the transformant was higher than wild type in tetracycline case. These results indicated that some biosynthesis genes or resistance genes for tetracycline biosynthesis in transformant might be repressed by seaR expression. Therefore, subsequent experiments, analysis of transcriptional pattern of genes for tetracycline production or resistance, are needed to confirm whether biosynthesis genes or resistance genes for tetracycline are repressed or not.