Issues

Actin network organization plays a critical role in regulating animal cell shape. We examined the Drosophila synaptotagmin-like protein (Btsz) in early embryo nuclear divisions, identifying a role for regulating pseudo-cleavage furrow stability. We showed that Btsz bundles actin filament networks in vitro.

Membrane contact sites dynamically adapt lipid metabolism to metabolic stress. Fujimoto and Tamura show that glucose starvation remodels the yeast nucleus–vacuole junction via Ypf1 and INSIG homologs, Nsg1 and Nsg2, pointing to a role for fatty acid elongation-linked membrane remodeling in the spatial control of ergosterol biosynthesis.

Phospholipase C-γ1 (PLC-γ1) plays key roles in cell migration, immune cell activation, and cancer progression. Appalabhotla et al. have developed a system enabling light-mediated recruitment of PLC-γ1 variants to dissect mechanisms underpinning cancer-associated hyperactivity, and they show that recruitment of active PLC-γ1 robustly directs fibroblast migration.

Curtis et al. show that the fungal “Cell Wall Integrity” repair pathway is silenced at contact sites between mating partners to allow cell wall degradation and fusion. They identify a cell wall protein needed to distinguish the contact site as a safe spot for wall removal.

Bacher et al. examine the evolution of microbial actin-based motility, a process that is important for spread of bacteria and viruses between host cells. They find evidence for considerable evolutionary flexibility in the mechanism and regulation of rickettsial actin-based motility, suggesting similar adaptability for other microbes.

Centriole microtubule architecture varies across species and developmental contexts. Chen et al. identify Ana1 as a regulator of centriolar doublet-to-triplet conversion and show that triplet microtubule integrity is crucial for sperm structure and male fertility.

Lysosomal cargo sorting from the early endosomes should involve mechanisms that prevent their recycling to the plasma membrane. Here, Chouhan P and Phogat Y et al. report that the small GTP-binding protein Arl8b recruits the Rab11a GAP, TBC1D9B, to inactivate Rab11a-mediated recycling of newly synthesized LAMP1 and mediate its efficient sorting to lysosomes.

Hurwitz et al. leverage a novel FRET-based approach to quantify conformational dynamics of Mfn1, a member of the dynamin superfamily that mediates mitochondrial outer membrane fusion. Their findings shed light on how GTP hydrolysis governs the conformational state of Mfn1, as well as the energetics underlying a key conformational transition.

Das and Chavez et al. demonstrate that in D. melanogaster, the histone chaperone NASP indirectly affects the nuclear import and chromatin deposition of H3. Their findings reveal a cytoplasmic function for NASP in preventing H3 aggregation in vivo. Live imaging in Drosophila embryos reveals that the H3 chaperone NASP does not directly affect H3 nuclear import or export rates. Reduced H3 levels in NASP-deficient embryos indirectly affect nuclear import and H3 deposition into chromatin. In vivo, cytoplasmic NASP prevents H3 aggregation and H3 aggregation and degradation are developmentally separable events.

Sakers et al. report that astrocytic NLs are functionally diverse proteins with unique intracellular protein–protein interactions. They show that Nedd4l binds to NL2 and ubiquitinates its intracellular domain, leading to changes in NL2 stability. In vivo, Nedd4l and NL2 ubiquitination are critical for astrocyte morphogenesis.

Chromosome segregation is triggered by separase and is abrupt and largely synchronous. Williams et al. show that synchronous chromosome segregation does not require separase-mediated positive feedback and that slight asynchrony may be unavoidable due to stochastic effects when only a few cohesin complexes remain at the time of sister chromatid separation.

Guerrero-Fonseca et al. provide evidence for a cellular cross talk through which neutrophils transfer proteases into endothelial cells to degrade cortactin, thus facilitating breaching of the vascular endothelium during inflammation.

Covill-Cooke et al. find that the ERMES lipid-transporting complex, long-thought to be an obligate heterotetramer, can be replaced by only one component: mitochondrially tethered Mmm1.

Eosinophils are associated with infection and pathological fibrosis. However, healthy small intestinal villi harbor dense populations of these granulocytes. Here, Petrova et al. show that eosinophils convert PDGFRβ+ fibroblasts to specialized villus smooth muscle cells, driving a developmental program for postnatal intestinal remodeling and maturation.

Yang et al. develop a light-based method to precisely modulate astrocytic Ca²⁺ signals via endogenous ER-IP3R pathways. Their approach reveals how local and global Ca²⁺ patterns differentially regulate organelle transport and astrocyte process growth, providing a versatile platform for dissecting Ca²⁺-dependent cell biology.

Zubia-Aranburu et al. review multiscale forces governing T-cell function, their disruption in disease, and how mechanobiology can improve immunotherapy design.

Thiam and Carpentier review seipin as a conformationally dynamic lipid rheostat that steers lipid fate and preserves cellular metabolic balance.

Sun and Chen highlight recent findings from Appalabhotla et al. showing how local PLC-γ1 activation directs cell motility.

Nicola Diny previews a study from Petrova et al., which reveals that eosinophils drive a developmental program for postnatal intestinal remodeling and maturation.