Dresden 2026 – scientific programme
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BP: Fachverband Biologische Physik
BP 27: Cell Mechanics I
BP 27.11: Talk
Thursday, March 12, 2026, 12:30–12:45, BAR/0205
A protein-DNA surface hydrogel mechanically reinforces the cell nucleus — •Yahor Savich1,2,3, Ramesh Adakkattil1, Pranay Mandal1,2,3, Valentin Ruffine4, Mareike Jordan1, Henrik Dahl Pinholt5, Elisabeth Fischer Friedrich4, Frank Jülicher2,3,4, Stephan Grill1,3,4, and Alexander von Appen1,4 — 1MPI-CBG, Dresden — 2MPI-PKS, Dresden — 3Center for Systems Biology Dresden — 4TUD, Dresden — 5MIT, Cambridge
Cells safeguard their genome while nuclei are deformed. The nuclear envelope is known to protect DNA from such mechanical stress, but how forces are buffered across the scales from individual DNA strands to the nucleus remains unknown. We show that the nuclear envelope protein LEM2 and the DNA-binding protein BAF, together with DNA, form an unconventional stiffening system. When DNA is held at a given force in optical tweezers, the addition of these proteins causes a force increase proportional to the initial force. This behaviour can be captured by an effective spring model that emerges from multivalent protein-protein and protein-DNA interactions. At the nuclear surface, the same components form an elastic surface hydrogel in which the multivalent interactions contract the surface hydrogel relative to its relaxed state, introducing a pre-stress. Using parameters obtained at the molecular scale, a continuum model of this surface hydrogel yields free-energy-minimizing nuclear shapes and an area stiffness that are in agreement with measurements in control and LEM2 knockdown cells. These results identify a load-bearing, mesoscale protein-DNA surface hydrogel that mechanically reinforces the nucleus.
Keywords: nuclear mechanics; surface hydrogel; elasticity; statistical mechanics; nuclear envelope