Kyushu University · Biochemistry, Genetics and Molecular Biology
Professor Yoshiki Katayama's research lab specializes in the design and development of stimuli-responsive polymers and molecular probes for biomedical applications, particularly in signal transduction monitoring and artificial gene regulation. The lab focuses on creating smart biomaterials that respond to specific cellular enzymes—such as protein kinase A, caspase-3, and PKC isoforms—through controlled conformational changes or disassembly. These systems enable real-time detection of enzymatic activity and precise control of gene expression, with applications in cancer diagnostics and targeted therapy. The lab also pioneers novel fluorescence probes using unique mechanisms like spin exchange for detecting biologically important molecules such as nitric oxide.
Figures are computed from collected data and may differ slightly.
New polymer−peptide conjugates, NIPAM−PEP and NIPAM−PEPEP, were designed and synthesized. These graft-type polymers contained a substrate peptide of protein kinase A (PKA), which forms one of the most important intracellular signals in cellular signal transduction. The NIPAM−PEP containing the N-isopropylacrylamide unit and the substrate peptide unit raised its lower critical solution temperature (LCST) from 36.7 to 40 °C in response to phosphorylation by activated PKA. The NIPAM−PEPEP containin
A fluorescent probe using a novel 'spin exchange' concept was developed for monitoring nitric oxide (NO) production. The probe is composed of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) labeled with acridine and N-dithiocarboxysarcosine (DTCS)-Fe(II) complex. When the non-fluorescent acridine-TEMPO was incubated with DTCS-Fe(II) complex in buffer solution, the nitroxide radical in the acridine-TEMPO interacted with the Fe(II) through a redox interaction. This interaction recovered the fluoresce
We describe two types of artificial gene-regulation systems responding to cyclic AMP-dependent protein kinase (PKA) or caspase-3. These molecular systems use newly synthesized cationic polymers, PAK and PAC. The PAK polymer includes substrate oligopeptide for PKA, ARRASLG, as receptor of PKA signal, while the PAC polymer possesses oligopeptide that is comprised of a substrate sequence of caspase-3, DEVD, and a cationic oligolysine, KKKKKK. These polymers formed stable complexes with DNA to total
The purpose of this study was to find protein kinase C (PKC) isozyme-specific peptides. A peptide library containing 1772 sequences was designed using Scansite and screened by MALDI-TOF MS and kinase activity assays for PKC isozyme-specificity. A peptide (Alphatomega; H-FKKQGSFAKKK-NH(2)) with high specificity for PKC alpha relative to other isozymes was identified. The peptide was phosphorylated to a greater extent by tissue lysates from B16 melanoma, HepG2, and human breast cancer, which had h
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