Mitochondria power the nucleus under pressure.

Mechanical confinement of cells, as occurs during processes like tumor cell invasion or immune cell trafficking, poses a pressure that can threaten nuclear integrity and cell viability. Recent findings illuminate a rapid adaptive mechanism by which cells under acute compressive stress rearrange their internal architecture to preserve nuclear functions. Upon confinement, mitochondria swiftly relocate to cluster around the nucleus (forming nuclear-associated mitochondria, NAM), entrapped by a web of endoplasmic reticulum (ER) and actin filaments. This proximity provides a localized surge of ATP within the nucleus, fueling energy-intensive nuclear processes, notably maintaining an open chromatin state and facilitating efficient DNA damage repair. This targeted energy delivery maintains nuclear chromatin accessibility, supports DNA repair mechanisms, and ensures sustained cell proliferation despite physical constraints. Here we provide a commentary on these findings, discussing the biological significance of mitochondria-nucleus repositioning, the role of nuclear ATP in safeguarding chromatin, and the broader implications for cellular fitness in development and disease.