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Toyoshi Fujimoto, September 15

SciLifeLab The Svedberg seminar series September 15

Toyoshi Fujimoto

Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan

Toyoshi Fujimoto has been engaged in the analysis of the membrane structure/function and the lipid droplet mainly by using electron microscopy. One of his current research interests lies in the molecular mechanism to generate the membrane asymmetry.

Electron microscopy to look at the nanoscale distribution of membrane lipids

Distribution of membrane proteins can be determined without much difficulty by microscopic techniques, whereas analysis of membrane lipids’ distribution is not easy due to various reasons. We have been working on an EM method to define distribution of membrane lipids at the nanometer level. The method, quick-freezing/freeze-fracture replica labeling method (QF-FRL), consists of 1) quick freezing to stop molecular motion instantaneously, 2) freeze-fracturing to split a membrane into two leaflets, 3) physically stabilizing membrane molecules by vacuum evaporation of platinum and carbon, 4) labeling of target molecules with probes, and 5) analysis by TEM. Using this method, we can analyze the two dimensional distribution of membrane lipids (and proteins) and the asymmetry between the lumenal and cytoplasmic leaflets. In this talk, I will show the results on several different lipids, including gangliosides and phosphoinositides [PI(4,5)P2, PI(3)P, PI(3,5)P2] and discuss the strength and weakness of QF-FRL in comparison with other methods.

Host: Ingela Parmryd