Abstract
Tracking individual proteins on the surface of live mammalian cells reveals complex dynamics involving anomalous diffusion and clustering into nanoscale domains. Theoretical models indicate that anomalous diffusion can be caused by vastly different processes. By performing time series and ensemble analysis of extensive single-molecule tracking in combination with stochastic modeling, the speaker shows that most trajectories violate the ergodic hypothesis, one of the cornerstones of statistical physics. In particular, ergodicity breaking manifests as substantial differences between the time-averaged and the ensemble-averaged observables. He finds that ergodicity breaking is caused by the transient localization of membrane proteins within nanoscale domains, such as endocytic pits. Furthermore, using a combination of dynamic super-resolution imaging and single-particle tracking, he observes that the actin cytoskeleton introduces barriers leading to the compartmentalization of the plasma membrane and that proteins are transiently confined within actin domains. The results show that the actin-induced compartments are scale free and that the actin cortex forms a self-similar fractal structure.
About the speaker
Prof Diego Krapf received his BSc in Physics in 1997, MSc and PhD in Applied Physics in 2000 and 2004 from Hebrew University of Jerusalem. He then started his research career as a postdoctoral researcher at Delft University of Technology from 2004 to 2007. In 2007, he joined Colorado State University as their Assistant Professor of Electrical and Computer Engineering and Biomedical Engineering. He has been the Associate Professor of Electrical and Computer Engineering and Biomedical Engineering there since 2013.
Prof Krapf’s research interests are interdisciplinary, covering single-molecule biophysics, random motion problems in stochastic physics, biomedical imaging techniques and their applications in biological questions, including cytoskeleton. He has been an editorial board member of Scientific Reports since 2016. He also served as the guest editor for Institute of Electrical and Electronics Engineers (IEEE) Journal of Selected Topics in Quantum Electronics (2015) and an editorial board member of IEEE Access (2012-2013).
Prof Krapf holds memberships at a number of professional bodies, including American Physical Society (APS), Biophysical Society, Institute of Electrical and Electronics Engineers (IEEE) and Optical Society of America (OSA).
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