Actin plays important roles in many biological processes, such as establishing cell polarization, accommodating protruding and retracting activities of motile cells, maintaining the physical integrity of the cell, and sensing environmental forces. All these processes are facilitated by the dynamical and mechanical properties of actin filaments, and their ability to exert or resist against forces generated in a cellular environment.
Actin filaments can assemble into a variety of architectures, including branched and crosslinked networks, parallel bundles, and anti-parallel contractile fibers. These structures provide architectural specificities for different regions of the cell, and can also organize into more complex actin-based machineries. We aim to understand how the native molecular architectures of actin-based cellular processes give rise to force generation and rigidity-sensing. We use cryo-electron tomography, and develop methodologies allowing for quantitative analysis of cellular actin networks architectures.
Figure 2. Cryo-electron tomography workflow (A-D) and actin architecture (E-G) in a thin protrusion assembled by Dictyostelium cells in response to a hole.[less]
Figure 2. Cryo-electron tomography workflow (A-D) and actin architecture (E-G) in a thin protrusion assembled by Dictyostelium cells in response to a hole.
Jasnin M., Ecke M., Baumeister W., Gerisch G.: Actin organization in cells responding to a perforated surface, revealed by live imaging and cryo-electron tomography. Structure, 24:1031-43, 2016
Jasnin M., Crevenna A.H.: Quantitative analysis of filament branch orientation in Listeria actin comet tails. Biophys J., 110:817-26, 2016
Heinrich D., Ecke M., Jasnin M., Engel U., Gerisch G.: Reversible membrane pearling in live cells upon destruction of the actin cortex. Biophys J., 106:1079-91, 2014
Jasnin M., Asano S., Gouin E., Hegerl R., Plitzko J.M., Villa E., Cossart P., Baumeister W.: Three-dimentional architecture of actin filaments in Listeria monocytogenes comet tails. Proc Natl Acad Sci U S A, 10:20521-6, 2013