Biophysical Society Thematic Meeting - June 28-July 1, 2015

New Biological Frontiers Illuminated by Molecular Sensors and Actuators

Monday Speaker Abstracts

FRET Imaging in Organoids and Mice Etsuko Kiyokawa . Kanazawa Medical University, Kahoku-gun, Japan.

Based on the principal of fluorescence resonance energy transfer (FRET), we are now able to observe the protein activities in the living cells. Using MDCK organoid and the FRET biosensor for small GTPase Rac1, we found Rac1activity is higher at the lateral than the apical plasma membrane in the mature cyst. Elevating the Rac1 activity at the apical membrane induced the luminal cell filling, indicating that the suppression of the Rac1 is required for maintenance of the epithelial structures. The transgenic mice expressing the FRET biosensors were established and recent development of two photon microscopy enables us to observe individual cells in the living mice. We time-lapse-imaged the activities of extracellular signal-regulated kinase (ERK) and protein kinase A (PKA) in neutrophils in inflamed intestinal tissue. ERK activity in neutrophils rapidly increased during spreading on the endothelial cells and showed positive correlation with the migration velocity on endothelial cells or in interstitial tissue. We are currently trying to observe cancer cell migration in the liver. References1. Mizuno R., KamiokaY., Kabashima K., Imajo M., Sumiyama K., Nakasho E., Ito T., Hamazaki Y., Okuchi Y., Sakai Y., Kiyokawa E., Matsuda M.: In vivo imaging reveals PKA regulation of ERK activity during neutrophil recruitment to inflamed intestines. J Exp Med: 211(6):1123-36, 2014.2. Yagi S., Matsuda M., Kiyokawa E.: Suppression of Rac1 activity at the apical membrane of MDCK cells is essential for cyst structure maintenance. EMBO Rep: 13(3), 237-243, 2012

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