Abstract

Abstract:

Being able to adequately react to one’s environment is essential for survival and procreation. Cilia are vital for the cell’s ability to sense its environment and rely on a process called intra flagellar transport (IFT) for their development, maintenance and function in signal-transduction. As a model, we study C. elegans chemosensory cilia. Motor proteins transport ciliary components along the polarized microtubule axoneme of the cilium. Among the cargoes of IFT are transmembrane proteins involved in signal transduction. We demonstrate the robust, extensive and reversible ciliary retraction upon external chemical stimulation. To elucidate the dynamics underlying this dramatic shift in protein distribution, we performed single-molecule imaging of the transmembrane protein OCR -2 in live C. elegans. Analysis of the single-molecule trajectories shows that, in dendrite and transition zone, active transport is the prevailing motility mode of OCR -2. In the proximal and distal segments, however, motility is a much more complex, location-specific interplay between active transport, normal diffusion and sub diffusion. At the tip, confinement of the membrane proteins plays an important role. Together, our data demonstrates an intricate interplay between modes of transportation that ensure the proper ciliary distribution of OCR -2. These insights in the dynamics of cellular signal-transduction contributes to a wider understanding of IFT dynamics and to cilia as chemosensory organelles.

Biography:

Erwin Peterman is a professor in Physics of Living Systems at the Vrije Universiteit Amsterdam. Currently he is also Head of the Physics and Astronomy Department. He studied Molecular Sciences at Wageningen University and did his PhD in the biophysics of photosynthesis at Vrije Universiteit Amsterdam. After a postdoc in the lab of W.E. Moerner (UC San Diego, Stanford University) he returned to the Vrije Universiteit and has become professor there. He is a single-molecule biophysicists who combines the development of advanced, often laser-based, techniques and their application to important biological problems. His instrument development focusses on single-molecule fluorescence microscopy, optical tweezers and acoustic force spectroscopy. He is cofounder of LUMICKS b.v. a company that develops single-molecule instrumentation and has sold them to labs all over the world. In his biological applications, Peterman focusses on understanding intracellular transport and the role of motor proteins therein and DNA and DNA -binding proteins.

Zoom: https://us02web.zoom.us/j/85143737777