Do mechanical forces alter the distribution and stoichiometry of the focal adhesion protein zyxin

CATALINA VON BILDERLING; LORENA SIGAUT; LAURA C. ESTRADA; LÍA I. PIETRASANTA

C.A.B.A.

Conferencia; Gregorio Weber Conference; 2011

Fluorescence Foundation

Mechanical forces play an important role in the organization, growth, maturation, and function of living tissues. Mechanotransduction, the process by which cells sense and respond to mechanical signals, is mediated by extracellular matrix, transmembrane integrin receptors, cytoskeletal structures and associated signaling molecules organized in flat, elongated and transient structures known as focal adhesions (FAs). In the presence of a mechanical stimulus, FAs are dynamically assembled and disassembled and this constant remodeling is presumably governed by the modulation of temporary interactions between its constituent proteins [1-2]. The understanding of the biophysical and molecular mechanisms underlying these events requires the development of techniques to identify the organization and dynamics of the FAs proteins in response to a mechanical stimulus. These techniques may have a high spatio-temporal resolution to detect transient and strongly localized events that occur in a region of the cell. N&B [3] (Number and Brigthness) allows the determination of the number and brightness of fluorescent molecules revealing their stoichiometry at each pixel of a confocal microscope image. In this work, we have studied the distribution and stoichiometry of the FAs protein zyxin in the presence and in the absence of a mechanical force [4]. We have expressed in epithelial mammalian living cells (HC11) zyxin protein tagged with green fluorescent protein (GFP) and obtained, as a function of an applied force, the stoichiometry of the zyxin aggregates by N&B analysis