Chul-Hong Kim
UPRRP College of Natural Sciences
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Publication
Featured researches published by Chul-Hong Kim.
Journal of Biological Chemistry | 2012
Jung-Woong Kim; Sang-Min Jang; Chul-Hong Kim; Joo-Hee An; Eun-Jin Kang; Kyunghee Choi
Background: TIP60 is involved in transcriptional regulation acting as a coactivator or corepressor. Also, TIP60 acetylates histones to modulate chromatin remodeling. Results: TIP60 enhances transcriptional activity of RelA/p65, which is the active subunit of NF-κB through their physical interaction. Conclusion: TIP60 is critical cofactor of RelA/p65 for transcription of NF-κB target genes. Significance: TIP60 is involved in the NF-κB pathway in hepatocarcinoma cells. The nuclear factor-κB (NF-κB) family is involved in the expressions of numerous genes, in development, apoptosis, inflammatory responses, and oncogenesis. In this study we identified four NF-κB target genes that are modulated by TIP60. We also found that TIP60 interacts with the NF-κB RelA/p65 subunit and increases its transcriptional activity through protein-protein interaction. Although TIP60 binds with RelA/p65 using its histone acetyltransferase domain, TIP60 does not directly acetylate RelA/p65. However, TIP60 maintained acetylated Lys-310 RelA/p65 levels in the TNF-α-dependent NF-κB signaling pathway. In chromatin immunoprecipitation assay, TIP60 was primarily recruited to the IL-6, IL-8, C-IAP1, and XIAP promoters in TNF-α stimulation followed by acetylation of histones H3 and H4. Chromatin remodeling by TIP60 involved the sequential recruitment of acetyl-Lys-310 RelA/p65 to its target gene promoters. Furthermore, we showed that up-regulated TIP60 expression was correlated with acetyl-Lys-310 RelA/p65 expressions in hepatocarcinoma tissues. Taken together these results suggest that TIP60 is involved in the NF-κB pathway through protein interaction with RelA/p65 and that it modulates the transcriptional activity of RelA/p65 in NF-κB-dependent gene expression.
Biochemical and Biophysical Research Communications | 2011
Joo-Hee An; Jung-Woong Kim; Sang-Min Jang; Chul-Hong Kim; Eun-Jin Kang; Kyung-Hee Choi
As a transcription factor, p53 modulates several cellular responses including cell-cycle control, apoptosis, and differentiation. In this study, we have shown that an actin regulatory protein, gelsolin (GSN), can physically interact with p53. The nuclear localization of p53 is inhibited by GSN overexpression in hepatocarcinoma HepG2 cells. Additionally, we demonstrate that GSN negatively regulates p53-dependent transcriptional activity of a reporter construct, driven by the p21-promoter. Furthermore, p53-mediated apoptosis was repressed in GSN-transfected HepG2 cells. Taken together, these results suggest that GSN binds to p53 and this interaction leads to the inhibition of p53-induced apoptosis by anchoring of p53 in the cytoplasm in HepG2 cells.
Cancer Letters | 2010
Sang-Min Jang; Jung-Woong Kim; Chul-Hong Kim; Daehwan Kim; Sangmyung Rhee; Kyung-Hee Choi
p19(ras) is an alternative splicing product of the proto-oncogene c-H-ras pre-mRNA. In this study, we identified a novel p19(ras)-binding protein, Neuron-Specific Enolase (NSE), using the yeast two-hybrid method. NSE is one of the enolase families that convert 2-phospho-d-glycerate (PGA) to phosphoenolpyruvate (PEP) in the glycolysis pathway. In both endogenous and over-expressed systems, we confirmed interactions between p19(ras) and NSE via co-immunoprecipitation assay. We also identified the interaction region of p19(ras), which is required for binding with NSE. When full-length p19(ras) and C-terminal region are bound to NSE, it inhibits the enzymatic activity of NSE. Furthermore, p19(ras) interacted with Enolase alpha (Enoalpha) and repressed its enzymatic activity in vitro. p19(ras) repressed lung cancer cell proliferation mostly increased by NSE in H1299 cells. Taken together, these results suggest that p19(ras) is a novel regulator to suppress cell proliferation in lung cancer through the interaction with NSE.
Molecular and Cellular Biology | 2012
Jung-Woong Kim; Sang-Min Jang; Chul-Hong Kim; Joo-Hee An; Kyung-Hee Choi
ABSTRACT Neural retina leucine zipper (Nrl), a key basic motif leucine zipper (bZIP) transcription factor, modulates rod photoreceptor differentiation by activating rod-specific target genes. In searching for factors that might couple with Nrl to modulate its transcriptional activity through posttranslational modification, we observed the novel interactions of Nrl with c-Jun N-terminal kinase 1 (JNK1) and HIV Tat-interacting protein 60 (Tip60). JNK1 directly interacted with and phosphorylated Nrl at serine 50, which enhanced Nrl transcriptional activity on the rhodopsin and Ppp2r5c promoters. Use of an inactive JNK1 mutant or treatment with a JNK inhibitor (SP600125) significantly reduced JNK1-mediated phosphorylation and transcriptional activity of Nrl in cultured retinal explants. We also found that Nrl activated rhodopsin and Ppp2r5c transcription by recruiting Tip60 to promote histone H3/H4 acetylation. The binding affinity of phospho-Nrl for Tip60 was significantly greater than that of the unphosphorylated Nrl. Thus, the histone acetyltransferase-containing Tip60 behaved as a coactivator in the Nrl-dependent transcriptional regulation of the rhodopsin and Ppp2r5c genes in the developing mouse retina. A transcriptional network of interactive proteins, including Nrl, JNK1, and Tip60, may be required to precisely control spatiotemporal photoreceptor-specific gene expression during retinal development.
Bioscience, Biotechnology, and Biochemistry | 2015
Chul-Hong Kim; Jung-Woong Kim; Sang-Min Jang; Joo-Hee An; Sang-Beom Seo; Kyung-Hee Choi
TIP60 can act as a transcriptional activator or a repressor depending on the cellular context. However, little is known about the role of the chromodomain in the functional regulation of TIP60. In this study, we found that TIP60 interacted with H3K4me3 in response to TNF-α signaling. TIP60 bound to H3K4me3 at the promoters of the NF-κB target genes IL6 and IL8. Unlike the wild-type protein, a TIP60 chromodomain mutant did not localize to chromatin regions. Because TIP60 binds to histones with specific modifications and transcriptional regulators, we used a histone peptide assay to identify histone codes recognized by TIP60. TIP60 preferentially interacted with methylated or acetylated histone H3 and H4 peptides. Phosphorylation near a lysine residue significantly reduced the affinity of TIP60 for the modified histone peptides. Our findings suggest that TIP60 acts as a functional link between the histone code and transcriptional regulators. As a code translator, TIP60 interacted to methylated or acetylated histone H3, H4, inducing open chromatin state for accessibility of transcription complexes.
Biochemical and Biophysical Research Communications | 2013
Sang-Min Jang; Eun-Jin Kang; Jung-Woong Kim; Chul-Hong Kim; Joo-Hee An; Kyung-Hee Choi
PUMA is a crucial regulator of apoptotic cell death mediated by p53-dependent and p53-independent mechanisms. In many cancer cells, PUMA expression is induced in response to DNA-damaging reagent in a p53-dependent manner. However, few studies have investigated transcription factors that lead to the induction of PUMA expression via p53-independent apoptotic signaling. In this study, we found that the transcription factor Sox4 increased PUMA expression in response to trichostatin A (TSA), a histone deacetylase inhibitor in the p53-null human lung cancer cell line H1299. Ectopic expression of Sox4 led to the induction of PUMA expression at the mRNA and protein levels, and TSA-mediated up-regulation of PUMA transcription was repressed by the knockdown of Sox4. Using luciferase assays and chromatin immunoprecipitation, we also determined that Sox4 recruits p300 on the PUMA promoter region and increases PUMA gene expression in response to TSA treatment. Taken together, these results suggest that Sox4 is required for p53-independent apoptotic cell death mediated by PUMA induction via TSA treatment.
Biochemical and Biophysical Research Communications | 2012
Chul-Hong Kim; Jung-Woong Kim; Sang-Min Jang; Joo-Hee An; Ki-Hyun Song; Kyung-Hee Choi
Pax6 is a member of the Pax family of transcription factors that contains a DNA binding paired-box and homeobox domain. In animals, including humans, Pax6 plays a key role in development, regulating organogenesis of the eye and brain. The current data show that histone acetyltransferase Tip60 physically interacts with Pax6 in developing post-natal day 4 (P4) mouse retinas. We also found that Tip60 binds with paired-domain of Pax6 using its chromo- and zinc-finger-containing regions, and that these protein interactions were needed for the effective full-transcriptional activation of Pax6. Furthermore, among the combinations of Pax6-target gene interactions using its two DNA binding domain, paired- and homeobox domain, Tip60 significantly enhanced the transcriptional activity of Pax6 on the paired-domain binding sequence (P6CON) containing reporter construct (pCON) than other homeo domain and chimera binding containing pP3 and pCON/P3 constructs. Taken together, these results suggest that Tip60 binds with Pax6 and that this physical interaction leads to the full-transcriptional activation of Pax6 during retina development.
FEBS Journal | 2011
Jung-Woong Kim; Sang-Min Jang; Chul-Hong Kim; Joo-Hee An; Eun-Jin Kang; Kyung-Hee Choi
The progression of muscle differentiation is tightly controlled by multiple groups of transcription factors and transcriptional coregulators. MyoD is a transcription factor of the myogenic basic helix–loop–helix family required for the process of muscle cell differentiation. We now show that Tip60 is required for myoblast differentiation via enhancement of the transcriptional activity of MyoD. Knockdown of Tip60 in C2C12 cells leads to a lack of ability to switch from proliferating myoblasts to differentiated myotubes. Ectopic expression of Tip60 increased MyoD‐mediated luciferase activity on the myogenic regulatory gene, myogenin. We also found that Tip60 physically interacts with MyoD using its chromo‐ and Zn‐finger‐containing region, and that these protein interactions were required for the effective transcriptional activation of MyoD. Furthermore, a chromatin immunoprecipitation assay revealed that Tip60 recruits MyoD on the myogenin promoter, and Tip60 also increases the levels of acetylated histones H3 and H4 during myogenic differentiation. Taken together, these findings suggest that Tip60 is an important co‐activator for MyoD‐mediated myogenesis in mouse myoblast C2C12 cells.
FEBS Letters | 2014
Joo-Hee An; Sang-Min Jang; Jung-Woong Kim; Chul-Hong Kim; Peter I. Song; Kyunghee Choi
The expression of the cell cycle inhibitor p21 is increased in response to various stimuli and stress signals through p53‐dependent and independent pathways. We demonstrate in this study that forkhead box A1/2 (FOXA1/2) is a crucial transcription factor in the activation of p21 transcription via direct binding to the p21 promoter in p53‐null H1299 lung carcinoma cells. In addition, histone deacetylase inhibitor trichostatin A (TSA)‐mediated upregulation of p21 expression was repressed by knockdown of FOXA1/2 in H1299 cells. Consequently, these results suggest that FOXA1/2 is required for p53‐independent p21 expression.
FEBS Journal | 2010
Jung-Woong Kim; Sang-Min Jang; Chul-Hong Kim; Joo-Hee An; Eun-Jin Kang; Kyung-Hee Choi
Protein phosphatase 2A plays an important role in balancing phosphorylation signals that are critical for cell proliferation and differentiation. Here, we report that Ppp2r5c (regulatory subunit of protein phosphatase 2A) expression was regulated by the transcription factor neural retina leucine‐zipper (Nrl) through enhancement of its transcriptional activity on the Ppp2r5c promoter. Using electrophoretic mobility shift assays and chromatin immunoprecipitation, we also found that Nrl bound directly to the Nrl‐response element on the Ppp2r5c promoter. The affinity of binding of Nrl to the Ppp2r5c promoter was tightly regulated during mouse photoreceptor development. Overall, these results suggest that Ppp2r5c expression is regulated by Nrl during retinogenesis through direct binding to the promoter region of Ppp2r5c.