Sperm flagella of highly divergent eukaryotic species share an architectural plan. Despite their ostensible ultrastructural similarities, mammalian sperm flagella beat with an asymmetric waveform, in contrast to the symmetrical beats of other eukaryotic flagella. Structural findings elucidate the molecular basis for this evolutionary divergence.

Recent studies offer new insight on the mechanisms of IP6-mediated HIV-1 capsid assembly. The immature Gag lattice enables enrichment of IP6 into virions, aiding capsid maturation. Structures of capsid protein (CA) assemblies reveal motifs serving as switches modulating the conformations of CA pentamers/hexamers and affect co-factor accessibility.

The RNA methyltransferase (MTase) METTL1 catalyzes N⁷-methylguanosine (m⁷G) modification at position 46 in human transfer RNAs (tRNAs). Its dysregulation drives tumorigenesis in many cancer types. Two papers now reveal the structural basis of this tRNA maturation event.

Tsirigotaki et al. unveil how adipokine Leptin induces trimerization of the Leptin receptor to form a cytokine-receptor assembly critical to body weight regulation, immunity, fertility and cancer.

Zhang et al. describe structures, diverse function and subunit-specific pharmacology of three major GluN2C- and GluN2D-incorporated NMDA receptors known to exist in the brain.

In this work, the authors show that the DREAM complex suppresses the expression of numerous DNA-repair proteins in somatic cells. Suppression of the DREAM complex, either by altering individual components in Caenorhabditis elegans or chemical inhibition in human cells and progeroid mice, results in increased resistance to various DNA-damage sources during development and aging.

The authors demonstrate that cells that are deficient in H3K9 trimethylation display more compact mitotic chromosomes decorated with aberrantly high H3S10 phosphorylation and H3K27 trimethylation. By quantitative proteomics, they show that H3K9 trimethylation is essential for mitotic bookmarking by Esrrb and thus for the maintenance of epigenetic memory during cell division.

Using cryo-EM structures, single-molecule fluorescence and electrophysiological studies, Kern et al. show how LRRC8A:C volume-regulated channels assemble into heteromers and use pore-bound lipids to block conduction in a closed state.

The authors perform a computational analysis of mutagenesis at non-B DNA structures formed by repetitive sequences. Having removed confounding factors, they present a landscape of mutagenesis different than previously thought, in which mechanisms such as the formation of abnormal secondary structures, polymerase slippage and occasional takeover by error-prone polymerases play an important role within, but not surrounding, the motifs.