Article SUMO protease SENP6 protects the nucleus from hyperSUMOylation-induced laminopathy-like alterations

The small ubiquitin-like modifier (SUMO) protease SENP6 disassembles SUMO chains from cellular substrate proteins. We use a proteomic method to identify putative SENP6 substrates based on increased apparent molecular weight after SENP6 depletion. Proteins of the lamin family of intermediate filaments show substan-tially increased SUMO modification after SENP6 depletion. This is accompanied by nuclear structural changes remarkably like those associated with laminopathies. Two SUMO attachment sites on lamin A/C are close to sites of mutations in Emery-Driefuss and limb girdle muscular dystrophy. To establish a direct link between lamin SUMOylation and the observed phenotype, we developed proximity-induced SUMO modification (PISM), which fuses a lamin A/C targeting DARPin to a SUMO E3 ligase domain. This directly targets lamin A/C for SUMO conjugation and demonstrates that enhanced lamin SUMO modification recapit-ulates the altered nuclear structure manifest after SENP6 depletion. This shows SENP6 activity protects the nucleus against hyperSUMOylation-induced laminopathy-like alterations.

Automated summary

The small ubiquitin-like modifier (SUMO) protease SENP6 disassembles SUMO chains from cellular substrate proteins. Proteins of the lamin family show increased SUMO modification after SENP6 depletion, accompanied by nuclear structural changes similar to laminopathies. Proximity-induced SUMO modification (PISM) directly targets lamin A/C for SUMO conjugation, recapitulating altered nuclear structure after SENP6 depletion. SENP6 activity protects the nucleus against hyperSUMOylation-induced laminopathy-like alterations.