Pauline Lascaux

The autophagy-lysosome system directs the degradation of a wide variety of cytoplasmic cargo such as damaged organelles, protein aggregates, and invading pathogens. The autophagy receptor IRGQ harbors two distinct LIR domains, with LIR1 exhibiting high selectivity for GABARAPL2. Proteomic, biochemical, and high-throughput microscopy studies reveal that the IRGQ-GABARAPL2 complex functions as a hub for the interaction between hATG8s and the autophagy initiation machinery, promoting their lipidation and overall autophagic flux. The interaction of IRGQ with GABARAPL2 is regulated via TBK1. Upon TBK1 activation, GABARAPL2 is phosphorylated on S10, which disrupts IRGQ-GABARAPL2 complexation and therefore its interaction with the autophagy initiation machinery, resulting in a reduction of the autophagic flux of GABARAPL2 and IRGQ-cargo, without affecting bulk autophagy. These findings broaden IRGQ’s role in autophagy, identifying it as an interaction hub for autophagy initiation that is negatively regulated by TBK1.

The nuclear envelope is a protective barrier for the genome and a mechanotransduction interface between cytoplasm and nucleus, whose malfunction disrupts nucleocytoplasmic transport, compromises DNA repair, accelerates telomere shortening, and promotes genomic instability. Mechanisms governing nuclear envelope remodeling and maintenance in interphase and post-mitotic cells remain poorly understood. Here, we report a role for dynamins, a family of essential brain-enriched membrane- and microtubule-binding GTPases, in preserving nuclear envelope and genomic homeostasis. Cells lacking dynamins exhibit nuclear envelope dysmorphisms, including buds with long narrow necks where damaged DNA frequently accumulates. These cells also show impaired autophagic clearance, reduced levels of key DNA repair proteins, and aberrant microtubules. Nocodazole treatment restores nuclear morphology and reduces DNA damage. Collectively, the data reveal that dynamins promote nuclear envelope homeostasis and removal of damaged DNA via their GTPase activity and interaction with microtubules, providing insights into mechanisms that uphold genome stability and counteract aging-related pathologies.

Efficient entry into S phase of the cell cycle is necessary for embryonic development and tissue homoeostasis. However, unscheduled S phase entry triggers DNA damage and promotes oncogenesis, underlining the requirement for strict control. Here, we identify the NUCKS1-SKP2-p21/p27 axis as a checkpoint pathway for the G1/S transition. In response to mitogenic stimulation, NUCKS1, a transcription factor, is recruited to chromatin to activate expression of SKP2, the F-box component of the SCF^SKP2 ubiquitin ligase, leading to degradation of p21 and p27 and promoting progression into S phase. In contrast, DNA damage induces p53-dependent transcriptional repression of NUCKS1, leading to SKP2 downregulation, p21/p27 upregulation, and cell cycle arrest. We propose that the NUCKS1-SKP2-p21/p27 axis integrates mitogenic and DNA damage signalling to control S phase entry. The Cancer Genome Atlas (TCGA) data reveal that this mechanism is hijacked in many cancers, potentially allowing cancer cells to sustain uncontrolled proliferation.