MECHANICAL CHARACTERIZATION OF THE INTERMEDIATE FILAMENTS NETWORK IN BHK CELLS

MARIANO SMOLER; LUCIANA BRUNO; VALERIA LEVI; CARLA PALLAVICINI

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Together with microtubules and actin filaments, intermediate filaments (IFs) are one of the main components of the eukaryotic cytoskeleton. IFs are crosslinked with the stiffer microtubules and actin networks, and contribute to the viscoelasticity of the cytoplasm and cell mechanical integrity. IFs have been studied in in-vitro assays, however, we still do not know key aspects of the organization of these filaments in the intracellular environment. IFs are composed of several members of a large family of cytoskeletal proteins, including nuclear lamins, which contributes to the structural integrity of the nucleus. In order to explore the mechanical properties of IFs in living cells, we transfected BHK cells with a vimentin-GFP containing plasmid and obtained images of the IFs network using confocal microscopy. From these images, we recovered the coordinates of individual fluorescent filaments with sub-pixel precision using an algorithm developed in our lab. By performing a Fourier analysis of the IFs shapes and a curvature analysis, we determined the persistence length of these filaments (a measure of the distance over which a filament appears approximately straight) and found a value of ~1.5 um which is in the order of the values determined in in-vitro conditions. We also analyzed the effect of microtubules depolymerization on the stiffness of IFs. This work contributes to the comprehension of the mechanical behavior of the cytoskeletal filaments to get a better insight into cell mechanics and organization.