Volume 26 Issue 4, April 2024

Despite the constant renewal of their components, cellular actin networks maintain their overall appearance, through a subtle balance of filament assembly and disassembly. This balance is key to the remodelling of cellular architecture. We discuss the significance of in vitro reconstitutions in deciphering the complexity of actin regulation.

Volume electron microscopy (vEM) generates large 3D volumes of cells or tissues at nanoscale resolutions, enabling analyses of organelles in their cellular environment. Here, we provide examples of vEM in cell biology and discuss community efforts to develop standards in sample preparation and image acquisition for enhanced reproducibility and data reuse.

β-propeller protein-associated neurodegeneration (BPAN) is caused by loss of functional WIPI4. A new study reports that depletion of WIPI4 induces ferroptosis via changes in mitochondrial membrane lipids, independently of the role of WIPI4 in autophagy, providing insights into the cause of neurodegeneration in BPAN.

Progeria, or premature ageing, is a devastating condition caused by defects in the nuclear envelope and is associated with systemic inflammation. A study now shows in animal models that inhibiting necroptosis, and particularly activity of the RIPK1 kinase, reduces inflammation and results in a meaningful extension in lifespan¹.

Organ morphogenesis begins with proliferation, which results in tissue pressures and site-specific YAP expression, nuclear translocation and signalling. A study now reports the involvement of anisotropy, localized pressure and YAP signalling in organizer-forming cascades, introducing a new chapter of molecular mechanobiology of organogenesis.

Eukaryotic transcriptional machinery often shows local enrichment in dynamic clusters at sites of high expression. A study of zebrafish embryos shows that such clusters can fine-tune the timing of zygotic genome activation by sequestering a component required for productive transcription, thus limiting its availability to other genes.

The tumour microenvironment produces nutrients that propel cancer development. New work finds that pancreatic ductal adenocarcinoma cells use one such nutrient, acetate, to alter protein acetylation, rerouting polyamine metabolism and promoting cell growth under acidosis—a finding with potential implications for treating this cancer.

Diverse, specialized immune cells defend against pathogens and cancer cells. A new study reveals the comprehensive lipid compositions of these cells, with unique lipidomes associated with various immune cell types. They show that cell-specific lipid compositions determine a key functional phenotype: their susceptibility to ferroptosis.

Shroff and colleagues report that cell proliferation induces localized mechanical compression in the tissue, driving the formation of the main mouse tooth signalling centre via differential YAP expression.

Alasaadi et al. report the role of hydrostatic pressure in regulating embryonic competence in the developing neural crest.

Zhu et al. show that loss of WIPI4, as seen in β-propeller protein-associated neurodegeneration, causes ferroptosis independently of autophagy due to an imbalance in phosphatidylethanolamine levels.

Ding et al. find a mechanism coordinating fatty acid and glucose supply. Glucose-driven Golgi phosphatidylinositol 4-phosphate levels impact the assembly of E3 ligase complex CUL7–FBXW8, controlling adipose triglyceride lipase levels and lipolysis.

Yang, Zhang et al. identify a non-canonical form of necroptosis driven by nuclear RIPK1-mediated nuclear membrane rupture as a result of ZMPSTE24 deficiency and defective prelamin A processing commonly observed in progeroid disorders.

Using single-molecule tracking and spatiotemporal mapping, Ling et al. show that the C-terminal domain of RNA polymerase II facilitates its dynamic confinement in subnuclear regions enriched in active genes, where it promotes targeted transcription.

Maneix, Iakova and colleagues report that cyclophilin A is a chaperone for, and regulator of, intrinsically disordered proteins within haematopoietic stem and progenitor cells, with potential effects on ageing-like phenotypes and lineage commitment.

Ugolini et al. show that transcription bodies regulate gene expression during zygotic genome activation in zebrafish development by sequestering CDK9 to limit the transcription of genes away from transcription bodies.

Murthy et al. demonstrate that cancer-associated fibroblast-derived acetate regulates polyamine homeostasis via an ACSS2–SP1–SAT1 axis in pancreatic cancer cells, thus enabling cell survival and tumour development under acidosis.

Duan et al. show that ACE2-dependent and ACE2-independent entry of SARS-COV-2 in epithelial cells versus myeloid cells differentially regulates viral replication and inflammatory responses, thereby contributing to COVID-19 progression and pathology.

Morgan, Pernes and colleagues perform mass spectrometry-based targeted lipidomics and provide a comprehensive lipid profile of human and mouse immune cells, which they then show confer differential ferroptosis susceptibilities.