Research Focus
My research focus is to understand how non-living matters construct living organism, by constructing artificial (minimal) cell in synthetic biological approach.
Artificial Cell
Cell is sustaining its living state through a large number of biochemical reactions within a lipid membrane vesicle.
Central dogma, which is the process of RNA and protein synthesis, is a core of intercellular reactions.
Shimizu et al. have reconstructed this process by combining the defined enzymes and factors involved in transcription and translation in 2001.
This in vitro system is functional also inside of artificially prepared membrane vesicle that mimics what actual living cell is doing.
Therefore, this artificial cell system is important as a platform technology for the reconstruction of living cell.
Although we are now able to construct artificial cell, the process of self-reproduction is not fully reconstructed so far.
Because self-reproduction is one of the essential properties of life, it reconstruction leads fundamental understanding of living system.
Self-reproduction of cell can be classified in replication of genetic information and cell envelope.
The former can be reconstructed by means of DNA or RNA replicase. However, reconstruction of membrane growth and division is still difficult because this is complicated and dynamical system spreading in a multi-scale from molecular to morphological levels.
For this problem, we are trying to reconstruct self-reproduction of membrane vesicle by synthesizing lipid molecules within the vesicle.
*Concerning bioethics, our approach is still out of consideration because we use non-living materials such as proteins or lipids.
We keep in mind to continue ethically valid research.
Drug discovery research
Cell membrane is composed of not only lipid but also many membrane proteins that undertake the roles of essential biochemical reactions on the membrane.
Especially, some membrane proteins, such as G-protein coupled receptor, are involved in serious disorders and these have been investigated as a target of drug discovery.
Therefore to obtain the target membrane receptor protein is crucial step in the process of drug discovery.
However, preparation of membrane protein is generally difficult and its takes a lot of time and cost.
About this problem we are developing a cell-free system that can synthesize functional membrane protein by combining the technologies of cell-free protein synthesis system and artificial lipid membrane.
Furthermore we are developing in vitro peptide screening system in order to discover a peptide that specifically binds to the target membrane protein.
We believe that our cell-free system will be a next platform technology in antibody drug discovery with low cost and fast.
Origin of life study
The biggest question how life emerged on the Earth remains as an enigma in the study of the origin of life.
We are trying to answer to this question based on the practical data obtained by artificial cell study and the geological knowledge about early Earth environment.
We believe that such synthetic biological approach will be a key for understanding the place and process of emergence of life.