Daiju Kitagawa

Phase Transition Dynamics by Innovative Measurement Techniques

Grant No.：JPMJCR22E1

Research Director

Daiju Kitagawa

Collaborator

Yuji Tokunaga	Assistant Professor Graduate School of Pharmaceutical Sciences The University of Tokyo
Kenjiro Hanaoka	Professor Faculty of Pharmacy/Graduate School of Pharmaceutical Sciences Keio University
Miho Yanagisawa	Associate Professor Graduate School of Arts and Sciences The University of Tokyo

Outline

In this research, we will establish an innovative measurement strategy to systematically analyze the phase transition processes in the formation of intracellular structures, by measuring the structure, physical properties, orientation, and fluidity of intracellular structures. Furthermore, we aim to elucidate the underlying mechanisms that drive the phase transitions and their physiological significance using the centrosome biogenesis as a model system. It has been shown that the centrosome and its components exhibit a wide range of physical properties in various biological contexts. Furthermore, we aim to theorize the intracellular phase transition system by validating the preexisting phase transition models in physics and by using data obtained from exhaustive measurements of phase transitions in cells and in vitro.

Akiko Satoh

Dynamics and cargo transports between TGN and endosomes

Grant No.：JPMJCR22E2

Research Director

Akiko Satoh

Collaborator

Akihiko Nakano	Senior Advisor・Deputy Director Center for Advanced Photonics RIKEN
Atsushi Matsuda	Senior researcher Advanced ICT Research Institute National Institute of Information and Communications Technology.

Outline

We found membranes of endosomes and trans-Golgi networks (TGN) are repeatedly connected and disconnected, and this novel membrane interaction is required for the export of anterograde cargoes from the trans-Golgi network. In this study, we will develop novel methods of perturbation and observation of transport. Together with our newly developed experimental system that can reversibly inhibit both dissociation and transport between TGN and endosome, we will elucidate the molecular and structural basis of cargo sorting and export from the trans-Golgi network.

Mikako Shirouzu

Elucidation of Dynamic Structure of DOCK Signalosome by Cryo-Electron Microscopy

Grant No.：JPMJCR22E3

Research Director

Mikako Shirouzu

Collaborator

Richard Wong	Professor Nano Life Science Institute(WPI-NanoLSI） Kanazawa University
Kento Kasahara	Assistant Professor Graduate School of Engineering Science Osaka University
Takamitsu Hosoya	Professor Institute of Integrated Research Institute of Science Tokyo
Junji Yamauchi	Professor Life Sciences Tokyo University of Pharmacy & Life Science

Outline

In this study, we aim to elucidate the molecular mechanism of the DOCK/Rho family signal transduction system that regulates cell motility and morphological changes, in which proteins cooperate to transmit stimuli on the plasma membrane interfaces. We will obtain high-resolution structures of various activation states in the reconstituted system, acquire positional information of intracellular molecules by cryo-electron tomography, and analyze their structures in the intracellular environment using labeled compounds to elucidate the mechanism of signalosome formation and its involvement in cell morphological changes at the molecular level.

Jun Suzuki

Lipid scrambling system regulated by higher-order structure interaction

Grant No.：JPMJCR22E4

Research Director

Jun Suzuki

Collaborator

Kazuhiro Abe	Professor Graduate School of Science Hokkaido University
Hitoshi Ishiwata	Chief Investigator Institute for Quantum Life Science National Institute for Quantum Science and Technology

Outline

Using an original screening approach developed by the group leader, we will identify the components of higher-order structures that regulate lipid scrambling. Cryo-EM (or X-ray) structural analysis will also be performed to elucidate the operative mechanisms of the identified factors at the molecular level. Factors that are well understood through these analyses will be reconstituted in lipid bilayers constructed directly on diamond nitrogen-vacancy centers (NV centers), and nanoscale NMR measurements of lipid scrambling will be performed.