Mechanical stress leads to changes in membrane biophysics, tubulin organization and cellular signaling.

VERSTRAETEN, S. V.; MACKENZIE, G.G; OTEIZA, P. I.

Pinamar, Buenos Aires, Argentina

Congreso; XLI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular, X Congreso Panamerican Association for Biochemistry and Molecular Biology y XX Reunión Anual Sociedad Argentina de Neuroquímica; 2005

The consequences of mechanical stress (MS) on membrane physical properties and on the activation of transcription factors NF-κB, AP-1, and NFAT were investigated in Jurkat T cells. Cells were submitted to 10-passages through a 200 μm diameter gauge. The fluidity of plasma membrane both, at the water-lipid interface and in the hydrophobic region of the bilayer, significantly decreased 1 min post-MS, recovering the initial value within the next 20 min. This effect was accompanied by the rearrangement of lipids in the lateral phase of the plasma membrane. MS was associated with a rapid increase in cellular Ca2+ 5 min after MS and with a rearrangement of cellular microtubules (increased soluble/polymerized β-tubulin). NFAT-, AP-1-, and NF-κB-DNA binding activities were measured by EMSA in total cell fractions. NFAT showed the highest DNA binding activity after 20 min post-MS, while NF-κB and AP- 1 had their maximal binding at 30 and 60 min post-MS, respectively. Results indicate that MS affects cell membrane physical properties leading to an increase in cellular Ca2+ and tubulin re-arrangements. These events could be involved in the activation of NFAT, NF-κB and AP-1.