PLoS Biology最新文献

Lysosomes are critical hubs for both cellular degradation and signal transduction, yet their function declines with age. Aging is also associated with significant changes in lysosomal morphology, but the physiological significance of these alterations remains poorly understood. Here, we find that a subset of aged lysosomes undergo enlargement resulting from lysosomal dysfunction in Caenorhabditis elegans (C. elegans). Importantly, this enlargement is not merely a passive consequence of functional decline but represents an active adaptive response to preserve lysosomal degradation capacity. Blocking lysosomal enlargement exacerbates the impaired degradation of dysfunctional lysosomes. Mechanistically, lysosomal enlargement is a transcriptionally regulated process governed by the longevity transcription factor SKN-1, which responds to lysosomal dysfunction by restricting fission and thereby induces lysosomal enlargement. Furthermore, in long-lived germline-deficient animals, SKN-1 activation induces lysosomal enlargement, thereby promoting lysosomal degradation and contributing to longevity. These findings unveil a morphological adaptation that safeguards lysosomal homeostasis, with potential relevance for lysosomal aging and life span.

Cell assemblies are considered fundamental units of brain activity, underlying diverse functions ranging from perception to memory and decision-making. Cell assemblies have generally been studied in relation to specific stimuli or actions, but this approach does not readily extend to more abstract constructs. An alternative approach is to assess cell assemblies without making reference to external variables, and instead focus on internal brain processes-by assessing assemblies by their endogenous ability to effectively elicit specific responses in downstream ("reader") neurons. However, this compelling idea currently lacks experimental support. Here, we provide evidence for assembly-reader communication. Large-scale cross-structural recordings in rats revealed that reader activation was genuinely collective, functionally selective, yet flexible, implementing both pattern separation and completion. These processes occurred at the time scale of membrane integration, synaptic plasticity, and gamma oscillations. Finally, assembly-reader couplings were selectively modified upon associative learning, indicating that they were plastic and could become bound to behaviorally relevant variables. These results support cell assemblies as an endogenous mechanism for brain function.

Bacteria encode for gene regulatory networks crucial for sensing and repairing DNA damage. Upon exposure to genotoxic stress, these transcriptional networks are induced in a temporally structured manner. A case in point is of the highly conserved SOS response that is regulated by the LexA repressor. Studies have proposed that affinity of LexA towards promoters of SOS response genes is the primary determinant of its expression dynamics. Here, we describe an additional level of regulation beyond LexA box properties that modulates the SOS response gene expression pattern. Using transcriptomic analyses, we reveal a distinct temporal hierarchy in the induction of SOS-regulated genes in Caulobacter crescentus. We observe that LexA box properties are insufficient in predicting the temporal hierarchy of these genes. Instead, we find that intrinsic promoter strength underlies the order of gene activation, with differential sigma factor association as one of the factors modulating gene expression timing. Our findings highlight a novel regulatory layer in SOS dynamics and underscore the importance of promoter properties in shaping bacterial stress responses.

Patient and carer perspectives, methodological rigor, and ethical considerations can all be successfully integrated into the biomedical funding process. Drawing on experiences with ERA-NET NEURON, we present a structured, scalable, and transferable model for funders to follow.

The suprachiasmatic nucleus (SCN), the central circadian pacemaker, orchestrates daily metabolic rhythms, yet its role in substrate selection and thermogenic adaptation under stress remains insufficiently understood. Here, we show that SCN lesioning abolishes the adaptive suppression of brown adipose tissue (BAT) thermogenesis typically observed during time-restricted feeding in subthermoneutral environments (TRF-STE), a paradigm that imposes concurrent nutrient and thermal stress. Contrary to wild-type responses, SCN-lesioned mice maintain elevated BAT thermogenic activity, despite impaired lipolysis, instead shifting toward glucose-driven heat production. This phenotype is accompanied by sustained sympathetic tone and β3-adrenergic receptor (ADRB3) signaling in BAT. Mechanistically, we identify a SCN-regulated ADRB3-S100B signaling axis underlying this metabolic reprogramming. S100B, a nutrient-sensitive calcium-binding protein, is upregulated in BAT following SCN disruption, where it promotes thermogenesis by stimulating brown adipocyte proliferation and suppressing senescence. Functional studies reveal that S100B is both necessary and sufficient for sustaining BAT thermogenesis under TRF-STE. Furthermore, diverse SCN disruption models, including light-induced circadian arrhythmia, N-Methyl-D-aspartic acid (NMDA) excitotoxicity, and Caspase-3-mediated ablation, consistently elevate S100B expression in BAT, reinforcing its role as a convergent effector of SCN-regulated metabolic adaptation. Thus, in intact animal, the SCN restrains the ADRB3-S100B module, gating BAT thermogenic output in accordance with energetic availability. Disruption of SCN output lifts this restraint, unmasking a latent ADRB3-S100B program that preserves thermogenesis when lipid fuel is limited. These findings reveal a previously unrecognized role of the SCN in governing thermogenic flexibility and fuel partitioning, and position the ADRB3-S100B axis as a potential target for mitigating circadian misalignment and metabolic disease.

Mitochondrial function and dynamics are essential for maintaining cellular homeostasis and overall health. Disruptions in these processes can contribute to various diseases, including cancer. The Hippo signaling pathway, a key regulator of tissue growth, plays a central role in cancer through its main effector YAP, known as Yki in Drosophila. In this model organism, Yki upregulation drives benign tissue overgrowth in imaginal discs. Our research demonstrates that the conserved metabolic regulator dPGC1 restricts Yki-driven tissue hyperplasia and helps maintain epithelial integrity in vivo. Combined Yki upregulation and dPGC1 depletion results in tumors characterized by enlarged mitochondria and the upregulation of genes promoting mitochondrial fusion, a condition that is both necessary and sufficient for Yki-driven oncogenic growth. We further demonstrate that mitochondrial enlargement is associated with increased levels of the cell cycle regulator Cyclin E, which plays a critical role in tumor development. These findings identify dPGC1 as a context-dependent tumor suppressor that coordinates mitochondrial dynamics and cell cycle regulation in response to oncogene activation, with implications for understanding cancer development in humans.

Diplonemids are among the most diverse and abundant protists in the deep ocean, have extremely complex and ancient cellular systems, and exhibit unique metabolic capacities. Despite this, we know very little about this major group of eukaryotes. To establish a model organism for comprehensive investigation, we performed subcellular proteomics on Paradiplonema papillatum and localized 4,870 proteins to 22 cellular compartments. We additionally confirmed the predicted location of several proteins by epitope tagging and fluorescence microscopy. To probe the metabolic capacities of P. papillatum, we explored the proteins predicted to the cell membrane compartment in our subcellular proteomics dataset. Our data revealed an accumulation of many carbohydrate-degrading enzymes (CDZymes). Our predictions suggest that these CDZymes are exposed to the extracellular space, supporting proposals that diplonemids may specialize in breaking down carbohydrates in plant and algal cell walls. Further exploration of carbohydrate metabolism revealed an evolutionary divergence in the function of glycosomes (modified peroxisomes) in diplonemids versus kinetoplastids. Our subcellular proteome provides a resource for future investigations into the unique cell biology of diplonemids.

The prevalent strategy of conserving nonmegafauna charismatic species may be counterproductive, if conservation impact measures are oversimplistic and do not facilitate the restoration of long-term ecosystems and their functions.

Membrane nanotubes serve as critical cytoskeletal structures that facilitate intercellular communication and signal transmission across distances in both plants and animals. Here, we report the role of microtubule (MT) nanotubes in rendering the Drosophila micropyle functional, a structure essential for sperm entry during fertilization. Our study highlights that MT-nanotubes emanate from the apical end of the specialized epithelial cells called the polar cells in late oogenesis, forming a narrow channel through the eggshell. Utilizing a combination of fly genetics, live cell imaging, and tissue immunochemistry, our research elucidates the structural and functional characteristics of the polar cell nanotube. We show that tubulin is vital for the formation of these nanotubes, which are enriched in the lateral membrane marker, Fasciclin III. Moreover, the overall polarity of the migrating border cell cluster is critical for the successful development of the micropyle. Notably, both lysosomal function and lysosomal trafficking within the polar cells are essential for the opening of the vitelline layer, further facilitating the micropyle's role in fertilization.

Neuronal activity and sensory experience regulate the subunit stoichiometry of synaptic N-methyl-D-aspartate subtype glutamate receptors (NMDARs), a critical determinant for brain development, synaptic plasticity, and a line of neurological disorders. Here we found that Ras and Rab interactor 1 (RIN1), a neuron-specific protein in the brain, played an important role in dictating synaptic NMDAR subunit composition in spinal cord somatostatin-positive (SOM+) neuron, a key component in the spinal circuit transmitting mechanical pain in mice. Our data showed that the protein level of RIN1 was low early after birth, which progressively increased with synapse maturation and promoted the switch from synaptic GluN2B- to GluN2A-containing NMDARs. In adult mice, the nerve injury-induced pathological pain paralleled a significant increase of RIN1 protein in spinal SOM+ neurons, which drove a new round of GluN2B-to-GluN2A switching at mature synapses. Our data revealed the molecular mechanisms by which RIN1 differentially regulated the synaptic trafficking of GluN2B and GluN2A receptors, and implied that RIN1-mediated pathological switch of NMDAR subunit composition strikingly altered the analgesic efficacy of distinct NMDAR subunit antagonists with the development of neuropathic pain.