- CENP-A is a homotypic octameric nucleosome
In this study, the authors use new reference models for 23 human centromeres and find that at all cell cycle phases centromeric CENP-A chromatin complexes are octameric nucleosomes with two molecules of CENP-A. This finding refutes previous models that have suggested that hemisomes may briefly transition to octameric nucleosomes.
- Dendritic loss of selective neuronal types
Mitochondrial dysfunction is associated with neuropathological events, but how it mediates loss of specific neuronal subtypes is unclear. Tsuyama et al. show that mitochondrial dysfunction triggers selective dendritic loss in class IV arborization neurons in a manner dependent on eIF2α phosphorylation and translation inhibition.
- Transcriptional programs of dendritic cell maturation
Dendritic cells promote either immunosuppressive or immunogenic T cell responses, but the transcriptional and epigenetic programs regulating these functions are unclear. Vander Lugt et al. dissect the distinct programs underlying the immunogenic and tolerogenic mature states of dendritic cells in vitro.
- HAP2/GCS1 is a gamete fusion protein
HAP2/GCS1 is essential for gamete fusion in plants, invertebrates, and protists. Valansi et al. demonstrate that a plant HAP2 is an authentic fusion protein that can fuse animal cells.
- Mtb replicates within necrotic human macrophages
Mycobacterium tuberculosis triggers macrophage cell death by necrosis, but it is unclear how this affects bacterial replication. Lerner et al. show that this pathogen replicates within necrotic human macrophages before disseminating to other cells upon loss of plasma membrane integrity.
- Osteoblastic Lrp4 regulates osteoclastogenesis
Lrp4 is mutated in patients with high-bone-mass diseases. Loss of Lrp4 in osteoblasts (OBs) increases bone formation by OBs and decreases bone resorption by osteoclasts through an unclear mechanism. Xiong et al. show that overproduction of extracellular adenosine in Lrp4-deficient OBs, which are derived from ATP hydrolysis and signals through A2AR and RANK, may underlie Lrp4 regulation of osteoclastogenesis.
- TorsinA-dependent rearward nuclear movement
In fibroblasts and myoblasts polarizing for migration, retrograde actin flow moves the nucleus rearward, orienting the centrosome toward the leading edge. The nucleus engages moving dorsal actin cables through linear arrays of nesprin-2G and SUN2 called TAN lines. In this study, Saunders et al. report that the nuclear envelope–localized AAA+ ATPase torsinA and its activator, LAP1, are required for TAN line assembly and retrograde dorsal actin cable flow.