3P173 FRAP experiments on actin and actin associate proteins in growth cones(Cell biology,Poster,The 52th Annual Meeting of the Biophysical Society of Japan(BSJ2014))

Abstract

Measurement of cell mechanical property is crucial for both understanding various cell functions and diagnosing cell disease. Previous atomic force microscopy (AFM), in which a stepwise change in frequency was employed, revealed that the cell complex shear modulus, G* exhibited a large cell-cell variation depending on frequency [1]. However the AFM method required a measurement time longer than the conventional force curve measurements. Here, we proposed a multi-frequency AFM for obtaining simultaneously G* of cell in a wide frequency range and demonstrated that this AFM technique allowed us to measure the powerlaw frequency dependence of G* [2] within several seconds.[1] Cai et al. Biophys.Using chemotaxis signal processing system, Escherichia coli (E. coli) regulates rotational direction of flagellar motor. When E. coli cell recognizes chemoattractant by transmembrane receptor, rotational direction of the flagellar motor changes to counterclockwise direction. In order to investigate kinetic property of the signal processing induced by chemoattractant, we statistically measured time course of directional biases of rotationing tethered cells. By using caged chemoattractants and hightemporal resolution measurement system (250 Hz), we traced precisely the directional biases triggered by photolysis of caged attractants. We would like to discuss about detail of the kinetic property in the signal processing induced by chemoattractant in this annual meeting. 3P171 蛍光相関分光法を用いた単一細胞由来のグルココルチコイド レセプター二量体形成と転写活性の定量 Quantification of glucocorticoid receptor homo-dimer and transcriptional activity in single cell by fluorescence correlation spectroscopyThe relationship between the amounts of homo-dimeric glucocorticoid receptor (GR) and transcriptional activity is studied using single-cell method combined with Fluorescence Correlation Spectroscopy (FCS) and microwell chip (FCS-microwell system). It is well-known that GR translocates to nucleus after ligand binding and then, homo-dimeric GR binds to genome and activates its functions as transcriptional factor. However, the relationship between the amounts of homo-dimeric GR and its transcriptional activity remains unclear, yet. In this study, FCSmicrowell system was established, namely the amounts of homo-dimeric GR and transcriptional activity were determined at single-cell lysate in microwell simultaneously by FCS and fluorescent reporter assay. 3P172 超解像顕微鏡法による上皮成長因子受容体クラスタリングの 定量解析Activation of epidermal growth factor receptor (EGFR), which evokes various cellular signaling, has been suggested to be regulated through diffusion-driven receptor clustering. For a precise analysis of the EGFR clustering, photo-activation localization microscopy (PALM) was employed to distinguish adjacent oligomers with a distance of shorter than the conventional optical resolution. The distribution of oligomer size quantified by a hierarchical clustering algorithm on the PALM data was distinct from that obtained by the previous methods. The localization accuracy has been improved for enabling i...