A biophysicist from VU University Amsterdam, Erwin PETERMAN (Dept of Physics and Astronomy, Physics of Living Systems, The Netherlands) will give a seminar on Thursday June 6th, 11:00 am in the Pierre Cotton Room (Institut Fresnel).
It will deal with single molecule detection and super-resolution imaging.
Abstract :
In the chemosensory cilia of Caenorhabditis elegans two kinesin-2-family motors, heterotrimeric kinesin-II and homodimeric OSM-3-kinesin, act together in a process called intraflagellar transport (IFT), essential for development and maintenance of the cilia. Along the middle segment, both these two kinesins drive transport, while in the distal segment only OSM-3-kinesin is active. How these motors work together in IFT, whether their mechanical coupling affects their motility and how their action is regulated is largely unknown. Using ultrasensitive, quantitative fluorescence microscopy we are able to track both motors at endogenous expression levels deep inside the living organism. We find that initially the two motors form an IFT-train together, but while moving along the middle segment kinesin-II gradually undocks, allowing the OSM-3-kinesin train to reach terminal velocity already at the middle segment. In addition, photo activation of fluorescent proteins allows precise control over fluorophore numbers and super-resolution tracking of individual motor clusters, revealing salient details of motor trajectories, such as direction reversals and track changes. Our results provide new insights into IFT and motor-driven processes in general.
Invitation Chercheur : Sophie Brasselet (MOSAIC) - Tel : +33 491 28 84 94
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