Speaker: Mathieu Coppey (Curie Institute Paris)
Subject: Dissecting back-to-front cell polarity with optogenetics
Date: Friday, September 16, 16:00-17:00
The first thing that strikes the audience as Mathieu Coppey starts his talk is his enthusiasm. When he introduces himself as a physicist moving into quantitative biology, his eyes twinkle. I believe this is a characteristic commonly observed when physicists talk about their moving into more biological research.
Coppey’s lab uses optogenetic techniques to perturb and study biological systems. In such approach, one uses light to observe and control f.e. cell organization. Some specific molecules undergo a conformational change upon being irradiated by light of a certain wavelength. Such conformational changes can correlate with the (in)ability for a receptor to bind its ligand. In this way, light can be used to externally perturb a biological system. In one of the epxeriments, Coppey shows a TIRF-microscopy video of the binding of a membrane protein and its ligand in a specified region of interest that is excited by the laser. In this region, the binding, and thus prolongued stay of the fluorescently-tagged ligand, results in increasing fluorescence signal.
Polarity in biology is a different topic studied by the group, using above-mentioned and complementary techniques. Polarity is a strange phenomenon with two extremes. Firstly, breaking a pencil into two pieces will yield two different pieces. By contrast, if you take a magnet and do the same, you will be left with two magnets that have two poles each. Somehow the magnet has an intrinsic polarity in its molecules. The same can be said for some biological tissues. If part of a developing embryo is removed, we may still see the same organism emerge, only lacking a specific limb. The matter at hand is not as black and white, so current research focuses on exploring and defining the in-between region of polarity in biology.