COE Study Abroad Project Report


Report on the Poster Presentation at Biophysical Society 49th Annual Meeting(U.S.A.)

Yukihiro Miyanaga, Doctoral course student

Report on participation in Biophysical Society 49th annual meeting

Schedule of the trip
2/11 Osaka (Japan) @Los Angels (USA)
2/12-16 Biophyscial Society 49th annual meeting, Long Beach (USA)
2/17-18 Los Angels (USA) @Osaka (Japan)

Meeting report
Biophysical society 49th annual meeting was held during February 12-16 in Long Beach, California. There were many symposiums and posters in this meeting because many researchers related to biophysics participated in this meeting, and they have diverse interests. I attended symposiums and posters related to single molecule biophysics and imaging techniques.
I made poster presentation entitled gsingle-molecule imaging of trimeric G protein in Dictyostelium cellsh on day 3. In this study, we observed single molecules of yellow fluorescent protein (YFP) fused alpha subunit of the heterotrimeric G protein (G alpha) in living Dictyostelium cells by total internal reflection fluorescence microscopy (TIRFM). We found that individual G alpha-YFP molecules came up to and off from the membranes, showing translocation of G proteins from cytoplasm to plasma membrane. We showed that the binding durations of Ga-YFP on the membrane were shorter than the bleaching time of the fluorescent protein. This result suggests G protein dissociate from membrane. We also showed the slower decay of total fluorescent intensity on plasma membrane of cell, which expressed G alpha-YFP. This result indicates fluorescent recovery by translocation of G alpha-YFP from cytoplasm. The binding duration of G alpha-YFP became shorter by cAMP stimulation, suggesting receptor-mediated acceleration of the dissociation of G proteins from membrane. Translocation of Ga is not commonly accepted although there are some reports about such phenomenon. In general, it is thought G protein located stably in plasma membrane. Therefore some people are skeptical about our date and I was questioned some points about our experiment. Anyway I had a meaningful discussion with them.

Perspective and future plans
In general, it is thought that GPCR and their coupled G protein operate on 2-dimensional plasma membrane. In contrast our data showed that G proteins operate 3-dimensionally. These results provide new insight in signal transduction of cell. However, our data allows of some dispute now. We have to show other supporting data. Additionally we must investigate the relationship between translocation of G proteins and sensibility of cell.

Finally, I would like to express to COE program my deepest gratitude for financial support of the trip.