Tokyo Institute of Technology · Biochemistry, Genetics and Molecular Biology
Professor Mako Kamiya's research lab specializes in the development of novel fluorescent and Raman probes for live-cell and in vivo imaging, with a focus on enzyme activity detection. The lab designs activatable probes that exhibit significant signal enhancement upon specific enzymatic activation, enabling high-contrast, single-cell resolution imaging in complex biological environments. Key research directions include the design of ratiometric and retention-based probes for hydrolases such as β-galactosidase and γ-glutamyltranspeptidase, as well as the application of electronic preresonance Raman signaling for multiplexed enzyme detection. The lab also pioneers bioorthogonal probe strategies for subcellular targeting and dynamic monitoring of intracellular processes.
Figures are computed from collected data and may differ slightly.
We identified a rhodol bearing a hydroxymethyl group (HMDER) as a suitable scaffold for designing fluorescence probes for various hydrolases. HMDER shows strong fluorescence at physiological pH, but phenolic O-alkylation of HMDER results in a strong preference for the spirocyclic form, which has weak fluorescence. As a proof of concept, we utilized this finding to develop a new fluorescence probe for β-galactosidase. This probe has favorable characteristics for imaging in biological samples: it
Beta-galactosidase is a widely used reporter enzyme, but although several substrates are available for in vitro detection, its application for in vivo optical imaging remains a challenge. To obtain a probe suitable for in vivo use, we modified our previously developed activatable fluorescence probe, TG-betaGal (J. Am. Chem. Soc. 2005, 127, 4888-4894), on the basis of photochemical and photophysical experiments. The new probe, AM-TG-betaGal, provides a dramatic fluorescence enhancement upon react
The LacZ gene, which encodes Escherichia coli β-galactosidase, is widely used as a marker for cells with targeted gene expression or disruption. However, it has been difficult to detect lacZ-positive cells in living organisms or tissues at single-cell resolution, limiting the utility of existing lacZ reporters. Herein we present a newly developed fluorogenic β-galactosidase substrate suitable for labeling live cells in culture, as well as in living tissues. This precisely functionalized fluoresc
We introduce here a new class of BODIPY-based Ca2+ indicators which can be derivatized with biological ligands that permit the localization of the indicators in living cells. The underivatized BODIPY-based Ca2+ indicator (BOCA-1) shows a 250-fold increase in fluorescence intensity upon Ca2+ binding. We also prepared its O6-benzylguanine (BG) derivative, BOCA-1-BG, which can be covalently and specifically linked to SNAP-tag fusion proteins in living cells. The indicator retains its properties as
γ-Glutamyltranspeptidase (GGT) is overexpressed in several types of cancer. Existing GGT-targeting fluorescence probes can image these cancers, but the fluorescent hydrolysis product leaks from the target cancer cells during prolonged incubation or fixation. Here, we present a functionalized fluorescence probe for GGT, 4-CH<sub>2</sub> F-HMDiEtR-gGlu, which is designed to generate an azaquinone methide intermediate during activation by GGT; this intermediate reacts with intracellular nucleophile
Raman probes based on alkyne or nitrile tags hold promise for highly multiplexed imaging. However, sensing of enzyme activities with Raman probes is difficult because few mechanisms are available to modulate the vibrational response. Here we present a general strategy to prepare activatable Raman probes that show enhanced Raman signals due to electronic preresonance (EPR) upon reaction with enzymes under physiological conditions. We identified a xanthene derivative bearing a nitrile group at pos
Prostate cancer (PCa) is a common malignant tumor among adult males, and convenient intraoperative detection of PCa would reduce the risk of leaving positive surgical margins, especially during nerve-sparing procedures. To achieve rapid, fluorescence-based visualization of PCa, we focused on the glutamate carboxypeptidase (CP) activity of prostate-specific membrane antigen (PSMA), a type II transmembrane glycoprotein that is attracting attention as a PCa biomarker. Based on our finding that aryl
The chemical biology of reactive sulfur species, including hydropolysulfides, has been a subject undergoing intense study in recent years, but further understanding of their "intact" function in living cells has been limited owing to a lack of appropriate analytical tools. In order to overcome this limitation, we developed a new type of fluorescent probe that reversibly and selectively reacts to hydropolysulfides. The probe enables live-cell visualization and quantification of endogenous hydropo
We have developed the first green-light-emitting, spontaneously blinking fluorophore (SBF), HEtetTFER. In combination with our near-infrared-light-emitting SBF (HMSiR), HEtetTFER allows dual-colour single-molecule localization microscopy (SMLM) in buffer solution without any additive and without photoactivation.
To achieve highly selective ablation of <i>lacZ</i>-positive cells in a biological milieu <i>in vivo</i>, we developed an activatable photosensitizer, SPiDER-killer-βGal, targeted to β-galactosidase encoded by the <i>lacZ</i> reporter gene. Hydrolysis of SPiDER-killer-βGal by β-galactosidase simultaneously activates both its photosensitizing ability and its reactivity to nucleophiles, so that the phototoxic products generated by light irradiation are trapped inside the <i>lacZ</i>-positive cells
Single-molecule localization microscopy (SMLM) allows the reconstruction of super-resolution images but generally requires prior intense laser irradiation and in some cases additives to induce blinking of conventional fluorophores. We previously introduced a spontaneously blinking rhodamine fluorophore based on an intramolecular spirocyclization reaction for live-cell SMLM under physiological conditions. Here, we report a novel principle of spontaneous blinking in living cells, which utilizes re
The Escherichia coli lacZ gene encoding β-galactosidase is a widely used reporter, but few synthetic substrates are available for detecting its activity with single-cell resolution in living samples. Our recently reported fluorogenic substrate SPiDER-βGal is suitable for this purpose, but its hydrolysis product shows green fluorescence emission, and a red-shifted analogue is therefore required for use in combination with green fluorescent protein (GFP) markers. Herein, we describe the developmen
The new star of Westerns: A highly sensitive fluorescence probe for alkaline phosphatase (ALP) based on a fluorescein derivative has been prepared and found to be suitable for use in Western blot analysis. The probe 1 is nonfluorescent but undergoes hydrolysis in the presence of ALP to yield a green-fluorescent derivative 2 and may be used in multicolor labeling in combination with other probes. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/content
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