The nuclear envelope is not just a barrier but a dynamic structure that regulates DNA packaging, replication, and responses to mechanical signals. Its key proteins, lamin B1 and the lamin receptor, gradually disappear with age, a process tied to nuclear deformation and cellular senescence. Until now, however, it was unclear which post-translational mechanisms govern their stability and whether these could be targeted to slow aging. The work sits at the intersection of longevity genetics and cell biology, alongside studies examining the breakdown of nuclear proteins and their role in aging.
The researchers combined genetic data from long-lived individuals (515 Ashkenazi Jewish centenarians) with tissue transcriptomic profiles from the GTEx database to identify genes that are both associated with longevity and change their expression with age. They then ran functional experiments on human mesenchymal stem cells: knockdown of UBE3C using short hairpin RNAs, generation of isogenic lines carrying the longevity variant via CRISPR/Cas9, quantitative proteomics, and co-immunoprecipitation to map interactions. To probe the degradation pathway, they used proteasome and lysosome inhibitors.
UBE3C emerged as the top candidate: its rare variant rs146755594 is associated with longevity (p=9.84E-04), and the gene's expression declines with age in 34 human tissues. Knockdown of UBE3C in stem cells led to premature senescence: the share of cells carrying the senescence marker SA-β-gal rose from 20% to 50%, while levels of lamin B1 and the LBR receptor fell. Conversely, the longevity variant delayed senescence and preserved these proteins. Mechanistically, UBE3C bound to LMNB1 and LBR through a domain spanning amino acids 290-692, but not through its ubiquitin ligase activity. Instead, it prevented their degradation in lysosomes, with the protein CKAP4 playing a key role by drawing lamin B1 to lysosomes in the absence of UBE3C.
This work is the first to link a specific ubiquitin ligase protein to the maintenance of the nuclear envelope during aging, and it shows that the protein acts not through the classic ubiquitination pathway but as a "guardian" that blocks autophagic degradation. This broadens our understanding of ubiquitin ligase functions and opens up a new UBE3C-LMNB1/LBR axis as a potential target for geroprotective interventions. Unlike neighboring studies that describe the breakdown of nuclear proteins as a marker of aging, this one proposes a specific molecular mechanism of protection, validated in isogenic models.
Further studies could test the role of UBE3C in in vivo model organisms, such as knockout mice or mice carrying the longevity variant. It will be important to determine whether this mechanism operates across different cell types and tissues, especially in the brain, where loss of lamin B1 is linked to neurodegeneration. It would also be promising to explore whether UBE3C function can be pharmacologically enhanced or CKAP4 blocked to slow aging.
The results could shape the development of therapies against age-related diseases tied to nuclear envelope dysfunction, such as progeria, neurodegeneration, and fibrosis. They also provide new targets for senolytics and geroprotectors.
The protective role of UBE3C needs to be confirmed in vivo in animal models, and it should be studied how the longevity variant affects lifespan and health. The interaction of UBE3C with CKAP4 and other components of autophagy also warrants detailed investigation.
This work directly addresses a fundamental problem of cellular aging: how proteostasis of the nuclear envelope is maintained and why it breaks down with age. It links longevity genetics to a specific molecular pathway, a rare achievement in gerontology.
Among 1799 genes involved in protein degradation, 87% change their activity with age. This highlights just how deeply aging affects the protein quality control system.
The idea of a nuclear "guardian" that could be enhanced to prolong cellular youth echoes the concept of geroprotectors in Kim Stanley Robinson's novel Aurora, where gene therapy is used to slow aging in the generations aboard a starship.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.