Reviews & Analysis

The interaction of non-immune and immune cells in the tumour microenvironment (TME) determines the quality of the immune attack on nascent tumour cells. A new study in melanoma cells shows that specific histone variants dampen the expression of cytokine genes in cancer-associated fibroblasts, leading to an immunosuppressive TME.

The mechanisms controlling lysosome abundance in cells and how changes in lysosome pool size impact physiological and pathophysiological processes are discussed.

Cells use various metabolic pathways to synthesize the building blocks for growth and proliferation. To ensure balanced growth, these biosynthetic processes must be tightly coordinated. We describe a molecular machinery that senses the cellular capacity to make lipids to regulate other biosynthetic processes — such as protein synthesis — accordingly.

A fast protocol for chemical cellular reprogramming reveals a diapause-like state, endogenous retrovirus activation and barriers to cell-fate transitions on the way to pluripotency. The system offers insights into manipulation of cellular regeneration and rejuvenation, two processes with great therapeutic potential.

In many species, a mother’s environment can impact offspring’s metabolism, but the mechanisms that mediate such intergenerational effects are unclear. In this issue, a study finds that the provisioning of a sphingolipid from mothers to offspring drives changes in offspring metabolism that protect against neuronal damage.

Sphingomyelin synthase 2 foci assemble at the leading edge of the basal membrane in migrating cells, and these foci eventually become sites of migrasome formation. Conversion of ceramide to sphingomyelin spurs migrasome growth and preserves the structural integrity of these organelles.

Pioneer transcription factors bind closed chromatin regions, alter local accessibility and activate target genes. A study reveals that the SOX9 transcription factor drives cell fate switching by activating hair follicle cell enhancers, while simultaneously repressing epidermal enhancers via sequestration of epigenetic factors.

Molecular insight into mechanisms that mediate the selective autophagy of lipid droplets (that is, lipophagy) has been lacking. This study identifies spartin, a protein mutated in a complex hereditary spastic paraplegia called Troyer syndrome, as a receptor that targets lipid droplets to the lysosome for degradation.

The Human BioMolecular Atlas Program (HuBMAP) presents its production phase: the generation of spatial maps of functional tissue units across organs from diverse populations and the creation of tools and infrastructure to advance biomedical research.

Reprogramming of somatic cells is an inherently inefficient process. A new study has now identified histone H3K36 methylation as a crucial reprogramming barrier that operates downstream of TGFβ signalling. Global inhibition of H3K36 methylation induced PRC2-dependent silencing of mesenchymal genes and dramatically increased reprogramming efficiency.

Class 3 phosphatidylinositol-3-kinase (PI3K) has a surprising nuclear function as a coactivator of the circadian clock Bmal1–Clock transcription factor complex for rhythmic purine nucleotide metabolism. This finding opens new avenues for establishing the roles of nuclear subunits of class 3 PI3K in metabolic homeostasis.

The compact state of chromatin induced by the methylation of lysine 9 on histone H3 has long been implicated in a heritable state of transcriptional repression. A study now shows that transient deposition of H3K9me3 helps to stabilize stalled DNA replication forks, while its reversal enables accurate fork restart.

The PHD–pVHL pathway is essential for oxygen-dependent prolyl hydroxylation of HIFA. A recent study identifies RIPK1 as a hydroxylation target in this pathway during hypoxia-induced cell death and presents a 2.8 Å resolution crystal structure of the pVHL–elongin B/C complex bound to hydroxylated RIPK1.

Mitochondria are dynamic organelles, changing their morphology and functional capacity in response to physiological and metabolic cues. A study uncovers a role for the typically nutrient-responsive mTORC2 during fasting in vivo to promote mitochondrial fission via the activation of a signalling pathway that involves NDRG1 and CDC42.

The rabbit is an important model species for developmental and translational research. Here, we used histological imaging and single-cell transcriptomics to characterize gastrulation and early organogenesis in the rabbit. We identified substantial transcriptional differences between the rabbit and mouse, highlighting the power of cross-species comparative genomics to elucidate early human development.

The nuclear envelope participates in the spatial regulation of DNA repair, but the mechanisms behind this are unclear. A study now reports that a nuclear envelope-localized nuclease, NUMEN/ENDOD1, guides the choice of DNA-repair pathway by inhibiting the resection of DNA ends and aberrant recombination, ensuring genome stability.

Disruptions in the autophagy–lysosome pathway in neurons have been implicated in Alzheimer’s disease. A study now reports that autophagy is also critical for disease-associated microglia surrounding amyloid plaques and is protective against microglial senescence and neuropathology in an Alzheimer’s disease mouse model.

Desmosomes and keratin are now found to regulate the distribution and dynamics of the endoplasmic reticulum (ER). This suggests that a range of ER functions may be coordinated by this intercellular adhesive and cytoskeletal network.

A new study shows that the enzymes involved in de novo pyrimidine synthesis and ferroptosis form a complex called the pyrimidinosome, which is controlled by AMPK. Cancer cells low in AMPK expression rely on the pyrimidinosome, suggesting that co-inhibition of AMPK and the pyrimidinosome represents a potential cancer treatment strategy.

Receptor-mediated endocytosis delivers low-density lipoproteins (LDLs) to late endosomes, from where cholesterol is trafficked to mitochondria. Zhou et al. report that LDL-containing endosomes fuse with mitochondria, supplying cholesterol for steroid biosynthesis and enabling mitochondrial degradation of the LDL receptor.