KIKUKAWA TakashiAssociate Professor

Laboratory of Biological Information Analysis Science
Research Theme
Biophysical studies on the membrane transporters
Research Keywords

rhodopsin, membrane transport, microbial rhodopsin, ion pump, flash photolysis, multidrug resistance

Overview of Research

Cell membrane has vital functions such as energy conversions, signal transductions, and capturing and expelling the substances. These functions are mainly fulfilled by the membrane proteins. We investigate functional mechanism of two types of membrane proteins, (1) microbial rhodopsins and (2) bacterial multidrug resistance transporters, by using the techniques of molecular biology and biophysics.

(1) Microbial rhodopsins
“Rhodopsin” is well-known photoreceptive pigment in retina of animal’s eye. Since 1999, genome projects have revealed a widespread presence of rhodopsin-like proteins in microorganisms. These microbial rhodopsins are multitalented: they include photoreceptors, light-activated ion pumps, light-gated ion channels, and even light-switchable enzymes. We investigate their molecular mechanisms.

(2) Bacterial multidrug resistance transporters
Multidrug transporters are widespread from bacteria to human and confer the multidrug resistance to the cells by actively expelling toxic compounds from the cytoplasm. Their mechanisms to recognize and export various compounds are intriguing subjects in the molecular science. We investigate the membrane topology and functional mechanism of bacterial small multidrug transporters.



Proteins are the chief actors on the biological phenomena. Why do these small molecules have high ability comparable to the artificial devices? We hope to find an answer to the question through the research on the functional mechanism of proteins.

Representative Publications



<Office Hour>
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E-mail: kikukawa[at]