• Molecules and Cells
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• v.42 no.7
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• pp.546-556
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• 2019

Protein phosphatase 4 (PP4) is a crucial protein complex that plays an important role in DNA damage response (DDR), including DNA repair, cell cycle arrest and apoptosis. Despite the significance of PP4, the mechanism by which PP4 is regulated remains to be elucidated. Here, we identified a novel PP4 inhibitor, protein phosphatase 4 inhibitory protein (PP4IP) and elucidated its cellular functions. PP4IP-knockout cells were generated using the CRISPR/Cas9 system, and the phosphorylation status of PP4 substrates (H2AX, KAP1, and RPA2) was analyzed. Then we investigated that how PP4IP affects the cellular functions of PP4 by immunoprecipitation, immunofluorescence, and DNA double-strand break (DSB) repair assays. PP4IP interacts with PP4 complex, which is affected by DNA damage and cell cycle progression and decreases the dephosphorylational activity of PP4. Both overexpression and depletion of PP4IP impairs DSB repairs and sensitizes cells to genotoxic stress, suggesting timely inhibition of PP4 to be indispensable for cells in responding to DNA damage. Our results identify a novel inhibitor of PP4 that inhibits PP4-mediated cellular functions and establish the physiological importance of this regulation. In addition, PP4IP might be developed as potential therapeutic reagents for targeting tumors particularly with high level of PP4C expression.

• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.278-288
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• 2019

In the present investigation, we attempted to design a protocol to develop a hybrid protein with better bioremediation capacity. Using in silico approaches, a Hybrid Open Reading Frame (Hybrid ORF) is developed targeting the genes of microorganisms known for degradation of organophosphates. Out of 21 genes identified through BLAST search, 8 structurally similar genes (opdA, opd, opaA, pte RO, pdeA, parC, mpd and phnE) involved in biodegradation were screened. Gene conservational analysis categorizes these organophosphates degrading 8 genes into 4 super families i.e., Metallo-dependent hydrolases, Lactamase B, MPP and TM_PBP2 superfamily. Hybrid protein structure was modeled using multi-template homology modeling (3S07_A; 99%, 1P9E_A; 98%, 2ZO9_B; 33%, 2DXL_A; 33%) by $Schr{\ddot{o}}dinger$ software suit version 10.4.018. Structural verification of protein models was done using Ramachandran plot, it was showing 96.0% residue in the favored region, which was verified using RAMPAGE. The phosphotriesterase protein was showing the highest structural similarity with hybrid protein having raw score 984. The 5 binding sites of hybrid protein were identified through binding site prediction. The docking study shows that hybrid protein potentially interacts with 10 different organophosphates. The study results indicate that the hybrid protein designed has the capability of degrading a wide range of organophosphate compounds.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.217-222
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• 2007

In the last 5 years the Epidermal Growth Factor Receptor (EGFR) has emerged as one of the most important targets for drug development in oncology. Monoclonal antibodies targeting the external domain of EGFR have been shown to have clinical benefits in colorectal and head and neck cancer when combined with chemotherapy and/or radiation. Also the targeting of the epithelial growth factor receptor (EGFR) kinase domain using the closely related inhibitors gefitinib and erlotinib has generally been ineffective against solid tumors, many of which over express the receptor. We found that there were some differential expressions according to primary antibodies of the EGFR protein which being used as one of the histological tumor markers for non-small cell lung cancer (NSCLC). We also found that there are some differential expressions according to antibodies, the pH of the antigen retrieval (AR) buffer solutions and kinds of enzymes. There were some differential expressions according to the secondary antibodies and the detection systems. We analyzed the correlations between the immunohistochemical expressions of the EGFR protein and the gene mutations of the EGFR. The differences between automatic stainers and manual staining methods were also evaluated.

• BMB Reports
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• v.35 no.2
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• pp.213-219
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• 2002

Malonyl-CoA decarboxylase (E.C.4.1.1.9) catalyzes the conversion of malonyl-CoA to acetyl-CoA. Although the metabolic role of this enzyme has not been fully defined, it has been reported that its deficiency is associated with mild mental retardation, seizures, hypotonia, cadiomyopathy, developmental delay, vomiting, hypoglycemia, metabolic acidosis, and malonic aciduria. Here, we isolated a cDNA clone for malonyl CoA decarboxylase from a rat brain cDNA library, expressed it in E. coli, and characterized its biochemical properties. The full-length cDNA contained a single open-reading frame that encoded 491 amino acid residues with a calculated molecular weight of 54, 762 Da. Its deduced amino acid sequence revealed a 65.6% identity to that from the goose uropigial gland. The sequence of the first 38 amino acids represents a putative mitochondrial targeting sequence, and the last 3 amino acid sequences (SKL) represent peroxisomal targeting ones. The expression of malonyl CoA decarboxylase was observed over a wide range of tissues as a single transcript of 2.0 kb in size. The recombinant protein that was expressed in E. coli was used to characterize the biochemical properties, which showed a typical Michaelis-Menten substrate saturation pattern. The $K_m$ and $V_{max}$ were calculated to be $68\;{\mu}M$ and $42.6\;{\mu}mol/min/mg$, respectively.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.629-633
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• 1998

In addition to selecting proteins for degradation by the 26S proteasome, ubiqitination appears to serve other regulatory functions, including for endosomal/lysosomal targeting, protein translocation, and enzyme modification. Currently, little is known how multiubiquitin chains are recognized by these cellular mechanisms. Within the 26S proteasome, one subunit (Mcb1/S5a) has been identified that has affinity for multiubiquitin chains and may function as a ubiquitin receptor. We recently found that a non-proteasomal protein p62 also preferentially binds multiubiquitin chains and forms a novel cytoplasmic structure "sequestosome" which serves as a storage place for ubiquitinated proteins. In the present manuscript, the role and regulation of p62 in relation to the sequestosomal function will be reviewed.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.69-72
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• 2016

Since the translocator protein (TSPO) is involved in neurodegeneration diseases, many scientists' interest has been focused on the development of a ligand targeting TSPO. A novel compound based on pyrazolo[1,5 -a] pyrimidine structure, DPA-714, has been studied and considered as a TSPO ligand with high affinity. In this highlight review, several researches for the novel radioligand for the translocator protein are illustrated.

• BMB Reports
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• v.35 no.1
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• pp.24-27
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• 2002

Apoptotic cell death is an active process mediated by various signaling pathways, which include the caspase cascade and the stress-activated protein kinase pathways. The caspase cascade is activated by two distinct routes: one from cell surface and the other from mitochondria. Activation of the route from cell surface requires the cellular components that include membrane receptors, adaptor proteins such as TRADD and FADD, and caspase-8, while activation of the other from mitochondria requires Apaf-1, caspase-9, and cytosolic cytochrome c. On the other hand, persistent stimulation of the stress-activated protein kinase pathway is also shown to mediate apoptosis in many cell types. Gene-targeting studies with jnk- or jip-null mice, in particular, strongly suggest that this signaling pathway plays a pivotal role in the cellular machinery for apoptosis.

• BMB Reports
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• v.51 no.10
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• pp.486-492
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• 2018

The CCN protein family is composed of six matricellular proteins, which serve regulatory roles rather than structural roles in the extracellular matrix. First identified as secreted proteins which are induced by oncogenes, the acronym CCN came from the names of the first three members: CYR61, CTGF, and NOV. All six members of the CCN family consist of four cysteine-rich modular domains. CCN proteins are known to regulate cell adhesion, proliferation, differentiation, and apoptosis. In addition, CCN proteins are associated with cardiovascular and skeletal development, injury repair, inflammation, and cancer. They function either through binding to integrin receptors or by regulating the expression and activity of growth factors and cytokines. Given their diverse roles related to the pathology of certain diseases such as fibrosis, arthritis, atherosclerosis, diabetic nephropathy, retinopathy, and cancer, there are many emerging studies targeting CCN protein signaling pathways in attempts to elucidate their potentials as therapeutic targets.

• Macromolecular Research
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• v.16 no.6
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• pp.481-488
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• 2008

Apoptosis is a natural cell suicide mechanism to maintain homeostasis. However, many of the diseases encountered today are caused by aberrant apoptosis where excessive apoptosis leads to neurodegenerative disorders, ischemic heart disease, autoimmune disorders, infectious diseases, etc. A variety of antiapoptotic agents have been reported to interfere with the apoptosis pathway. These agents can be potential drug candidates for the treatment or prevention of diseases caused by dysregulated apoptosis. Obviously, world-wide pharmaceutical and biotechnology companies are gearing up to develop antiapoptotic drugs with some products being commercially available. Polymeric drug delivery systems are essential to their success. Recent R&D efforts have focused on the chemical or bioconjugation of antiapoptotic proteins with the protein transduction domain (PTD) for higher cellular uptake with antibodies for specific targeting as well as with polymers to enhance the protein stability and prolonged effect with success observed both in vivo and in vitro. All these different fusion antiapoptotic proteins provide promising results for the treatment of dysregulated apoptosis diseases.

• Biomolecules & Therapeutics
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• v.32 no.2
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• pp.183-191
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• 2024

The Unfolded Protein Response (UPR) serves as a critical cellular mechanism dedicated to maintaining protein homeostasis, primarily within the endoplasmic reticulum (ER). This pathway diligently responds to a variety of intracellular indicators of ER stress with the objective of reinstating balance by diminishing the accumulation of unfolded proteins, amplifying the ER's folding capacity, and eliminating slow-folding proteins. Prolonged ER stress and UPR irregularities have been linked to a range of neuropsychiatric disorders, including major depressive disorder, bipolar disorder, and schizophrenia. This review offers a comprehensive overview of the UPR pathway, delineating its activation mechanisms and its role in the pathophysiology of neuropsychiatric disorders. It highlights the intricate interplay within the UPR and its profound influence on brain function, synaptic perturbations, and neural developmental processes. Additionally, it explores evolving therapeutic strategies targeting the UPR within the context of these disorders, underscoring the necessity for precision and further research to effective treatments. The research findings presented in this work underscore the promising potential of UPR-focused therapeutic approaches to address the complex landscape of neuropsychiatric disorders, giving rise to optimism for improving outcomes for individuals facing these complex conditions.