Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Polyglutamine (polyGln) expansions induce protein misfolding and aggregation into fibrillar deposits, which are believed to underlie forms of neurodegeneration through a mechanism involving gain of toxic function. Polyalalanine expansions are now shown to differ from polyGln in kinetics of aggregation, morphology of aggregates and mechanism of toxicity.
The mechanisms guiding the substrate specificity of kinases are still poorly understood. Two recent reports provide further insights into how the epidermal growth factor receptor (EGFR) tyrosine kinase recognizes targets by identifying a new consensus motif that requires a Src-mediated priming phosphorylation.
Telomerase is a unique reverse transcriptase in that it repetitively uses a short piece of its RNA component as template to synthesize DNA. A new crystal structure of a part of the Tetrahymena telomerase ribonucleoprotein reveals how reverse transcription is limited to this specific template region.
Newly synthesized 60S ribosomal subunits are licensed for translation through the release of the antiassociation factor eIF6. A new study shows by cryo–electron microscopy how eIF6 eviction results from a long-range allosteric cascade that involves SBDS, the protein mutated in Shwachman-Diamond syndrome.
The crystal structure of a prokaryotic proton-driven fumarate transporter, the first for the diverse SLC26 transporter family, reveals a rare transmembrane-segment topology. The opposite orientation of two short central helices leads to the formation of a dipole-mediated anion-binding site, which is made alternately accessible to either side of the membrane through the rocking movement of the core and gate domains of the transporter.
How is cellular cargo delivered at the right time and the right place, in response to the right signal? A key new piece in this fascinating biological puzzle has just been revealed.
The cellular 'alarmone' molecule ZTP accumulates when a critical cellular metabolic pathway is starved for substrate. The high-resolution structure of ZTP bound to its RNA-based sensor reveals unexpected strategies used by RNA to specifically recognize small-molecule ligands within the complex cellular mixture.
Two studies using chromosome conformation capture (3C) analyses in the Gram-positive bacterium Bacillus subtilis have revealed a global pattern of chromosome organization that originates from loading sites of the Smc–ScpAB complex. Loading Smc–ScpAB at a single genomic location is sufficient to promote genome-wide folding of DNA into a well-defined structure.
Export of effector proteins is crucial for the virulence program of the malaria parasite Plasmodium falciparum. A crystal structure of the Plasmodium vivax processing enzyme essential for protein export reveals noncanonical aspartic protease features and provides an avenue for antimalarial drug development.
Totipotency, the ability of early embryonic cells to generate a complete adult organism as well as extraembryonic tissue, is a fleeting property found only in very early embryonic cells. A breakthrough study now shows that inhibition of DNA replication–linked nucleosome assembly causes embryonic stem cells to resemble totipotent cells. Notably, inhibition of chromatin assembly stimulates reprogramming during somatic-cell nuclear transfer experiments.
Plants protect themselves from fluctuating high-light conditions by dissipating a large part of their absorbed energy as heat, in a process that requires the protein PsbS. The structure of PsbS opens new possibilities for understanding the mechanism of photoprotection in plants.
The eukaryotic 26S proteasome is responsible for degrading virtually any protein with an appropriate ubiquitin signal, and in the process ubiquitin is spared and recycled. Two studies of the proteasome-associated deubiquitinase UBP6 now shed light on how deubiquitination coordinates the cycle of substrate processing.
MCM2, a component of the replicative helicase, can bind histones H3–H4 in both tetrameric and dimeric form, depending on the presence of the histone chaperone ASF1. A structural analysis of the complexes now sheds light on key domains in the MCM2 protein that prove important for cell proliferation.
Two new studies reveal mechanistic insights into how neurons control the assembly of SNARE complexes and the rapid fusion of synaptic vesicles. Structural, biophysical and functional experiments are combined to elucidate the roles of two critical regulators: Munc13 and synaptotagmin.
Ten years ago, the repulsive guidance molecules (RGMs), a family of three glycosylphosphatidylinositol–anchored glycoproteins, were identified as highly specific co-receptors of the bone morphogenetic proteins (BMPs). Newly reported crystal structures provide exciting insights into how RGM co-receptors may modulate BMP signaling.
How do molecular interactions determine the period length of a circadian oscillator? In mammals, a disordered region of the BMAL1 transcription factor that is able to interact with activators or repressors seems to perform this function.
Sex-determining transcription factors recognize their genomic target sites through mechanisms of DNA base-and-shape readout in combination with cooperative binding. Murphy et al. reveal that for one such transcription factor, DMRT1, the DNA sequence-and-shape features of its binding sites determine whether it binds DNA as a dimer, trimer or tetramer; they also characterize protein-DNA contacts that affect gender phenotypes in flies and humans.
