Scientists from the Czech Academy of Science, Institute of Microbiology, have currently published an article in Biomolecules journal, that exhibits a novel insight about the role of focal adhesion kinase (FAK) and its interacting partner Rack1 in the development of the cell rear and thus the establishment of front-rear polarity with the reorganization of cell mass in spreading Rat2 fibroblasts.

FAK serves as a regulator of cell migration through focal adhesion turnover and trailing edge retraction. It is well known that the non-protruding region defines the front-rear polarity axis of polarized cells. Failure to establish the non-protruding cell rear was demonstrated in this article as a feature of FAK or Rack1 depleted cells. The study revealed that FAK-depleted cells formed two distally protruding regions creating an elongated phenotype that is incapable of defining the cell front and rear. Rack1-depleted cells acquired a large rounded phenotype with radial symmetry. Interestingly, the average dry mass was increased in both FAK- and Rack1-depleted cells by 54% and 131% respectively. Characterization of fibroblast morphology and cell mass dynamics in FAK- and Rack1-depleted cells were also precisely quantified.

In this research, Telight Q-Phase, based on the technology of coherence-controlled holographic microscopy, provides high phase detection sensitivity that produces high-quality quantitative phase images which significantly could serve not only to determine cell outline but also to quantify any slight accumulation of cell mass within the polar edges of fibroblasts. Good to mention that Q-Phase combines both quantitative phase imaging and fluorescence. This combination enabled authors to confirm that the protruding edges of the migrating control cells included higher dry mass values than the transition region behind it which was correlated with the localization of vasodilator-stimulated phosphoprotein “GFP-VASP, stains protruding membranes and focal adhesions localization”.