Figure 5.

Propagation of external mechanical force from integrins to chromatin [124]. External mechanical forces applied to the cell surface are propagated via integrins and tensed actin-myosin cytoskeleton to LINC complexes and nuclear lamins in the nuclear lamina. The forces are then transferred to the chromatin through heterochromatin protein (HP1), Barrier-to-autointegration factor (BAF) proteins, and other molecules. The forces transferred to the chromatin stretch deform the chromatin segment that contains the DHFR gene. The deformation and stretching of chromatin facilitate binding of transcription factors to the DHFR gene for the upregulation of the DHFR gene transcription. The external mechanical force was provided by ferromagnetic beads attached to integrins in a magnetic field. The magnetic stress was 17.5 Pa.