Kohsuke Gonda

Changes in membrane morphology and membrane protein dynamics based on its fluidity are critical for cancer metastasis. However, this subject has remained unclear, because the spatial precision of previous in vivo imaging has been limited to the micrometer level and single molecule imaging is impossible. Here, we have imaged the membrane dynamics of tumor cells in mice with a spatial precision of 7-9 nm under a confocal microscope. A metastasis-promoting factor on the cell membrane, protease-acti

Contrast agents are often used to enhance the contrast of X-ray computed tomography (CT) imaging of tumors to improve diagnostic accuracy. However, because the iodine-based contrast agents currently used in hospitals are of low molecular weight, the agent is rapidly excreted from the kidney or moves to extravascular tissues through the capillary vessels, depending on its concentration gradient. This leads to nonspecific enhancement of contrast images for tissues. Here, we created gold (Au) nanop

The quantitative sensitivity and dynamic range of conventional immunohistochemistry (IHC) with 3,3'-diaminobenzidine (IHC-DAB) used in pathological diagnosis in hospitals are poor, because enzyme activity can affect the IHC-DAB chromogenic reaction. Although fluorescent IHC can effectively increase the quantitative sensitivity of conventional IHC, tissue autofluorescence interferes with the sensitivity. Here, we created new fluorescent nanoparticles called phosphor-integrated dots (PIDs). PIDs h

Overexpression of HER2 is one of the major causes of breast cancer, and therefore precise diagnosis of its protein expression level is important. However, current methods estimating the HER2-expression level are insufficient due to problem with the lack of quantification. This might result in a gap between diagnostics and therapeutics targeting HER2. Therefore, a new effective diagnostic method is needed. We developed a new immunohistochemical (IHC) technique with quantum dots (QD)-conjugated tr

In breast cancer, the prognosis of human epidermal growth factor receptor 2 (HER2)-positive patients (20-25%) has been dramatically improved by the clinical application of the anti-HER2 antibody drugs trastuzumab and pertuzumab. However, the clinical outcomes of HER2-negative cases with a poor prognosis have not improved, and novel therapeutic antibody drugs or diagnostic molecular markers of prognosis are urgently needed. Here, we targeted protease-activated receptor 1 (PAR1) as a new biomarker

The ciliated protist, Tetrahymena thermophila, possesses one oral apparatus for phagocytosis, one of the most important cell functions, in the anterior cell cortex. The apparatus comprises four membrane structures which consist of ciliated and unciliated basal bodies, a cytostome where food is collected by oral ciliary motility, and a cytopharynx where food vacuoles are formed. The food vacuole is thought to be transported into the cytoplasm by a deep fiber which connects with the oral apparatus

Tetrahymena p85 differs in mobility in two-dimensional SDS-polyacrylamide gel electrophoresis between wild-type and temperature-sensitive cell-division-arrest mutant cdaA1 cell extracts, and is localized to the presumptive division plane before the formation of the division furrow. The p85 contained three identical sequences which show homology to the calmodulin binding site of Ca(2+)/calmodulin dependent protein kinase Type II in Saccharomyces cerevisiae. We found the p85 directly interacts wit