Browse Articles

The Gabija system constitutes one of the most prevalent anti-phage defense systems and is composed of GajA and GajB. Here, using cryo-EM and biochemistry, the authors show that GajA and GajB form a supramolecular complex with a stoichiometry of 4:4 to promote anti-phage defense.

The authors report that the γ-tubulin ring complex (γ-TuRC), an essential regulator of microtubule formation, selectively nucleates microtubules with 13-protofilaments and characterize the structural transformations associated with this function.

Using cryo-electron tomography, Dendooven et al. determined the structure of the native budding yeast γ-tubulin ring complex (γTuRC) capping spindle microtubules and showed that γTuRC adopts an active closed conformation to function as a perfect geometric template for microtubule nucleation.

Here, using cryo-EM, biochemistry and cell biology, the authors reveal the unique assembly, catalytic mechanism, multimodal substrate recruitment and regulation of the atypical ubiquitin ligase complex CUL9–RBX1.

Precise protease positioning and gating of the proteasome core require the ordered assembly of 28 subunits. Cryo-EM structures of seven intermediates visualize five dedicated chaperones and three propeptides mediating step-by-step assembly of the human 20S proteasome.

To prevent promiscuous protein degradation, proteasomes are initially assembled as inactive complexes. Their activation is autocatalytic and coupled to assembly. Here the authors uncover key aspects of the autocatalytic activation mechanism.

The authors describe the structure of an adenylyl cyclase 5 and Gβγ complex, which potentially influences a neural signalling pathway modulating motor function. Mutations in the Gβγ binding site on AC5 are linked to heritable forms of dyskinesia.

The authors report the structures of human CHT1 in the outward-open, inward-occluded and inward-open states, reveal the mechanism of HC-3 inhibition and choline recognition and elucidate the regulatory role of the intracellular helix IH1.

Here the authors structurally characterize respiratory supercomplexes, revealing that, in addition to the known ‘canonical’ respirasome, mammalian mitochondria contain two novel respirasome types, one of which incorporates supercomplex assembly factor SCAF1.

Pregnancy loss is common in humans, but maternal genetic factors modulating its incidence are largely unknown. In a meta-analysis of genome-wide association studies, researchers identified a genetic variant that seems to increase risk of pregnancy loss by dysregulating meiotic recombination between homologous chromosomes during egg formation.

G protein-coupled receptors (GPCRs) with no known endogenous ligand are termed orphans. Deorphanization of a GPCR involves identifying the ligand, which can be a painstaking exercise. In this Comment, we discuss the challenges in the process, its role in drug discovery and alternative approaches to characterizing orphan GPCRs.

Phosphoinositide 3-kinase γ plays critical roles in neutrophil chemotaxis and cancer metastasis. Here, using cryo-EM and functional studies, the authors reveal how two molecules of a key activator, Gβγ, bind to and alter the conformation of the enzyme.

Cryo-electron microscopy of brain tissue from two individuals with Down syndrome showed amyloid-β (Aβ) and tau filaments identical to those found in individuals with sporadic or dominantly inherited Alzheimer disease (AD), but also two types of Aβ₄₀ filaments with distinct structures different from those previously reported in AD and cerebral amyloid angiopathy.

Here, using cryo-EM, authors reveal that amyloid-β and tau are identical in Alzheimer disease and Down syndrome. This has implications for assessing whether adults with Down syndrome could be included in Alzheimer disease clinical trials.

The identification of sodium and potassium currents as underlying action potential propagation, more than 70 years ago, opened a new avenue of research into the role of ion channels. In this Comment, we present our personal perspectives of the field, from the identification of Shaker as a potential potassium channel to the mechanistic insights available to us today.

Here, four cryo-EM structures of Mtb OppABCD reveal an assembly of a cluster C substrate-binding protein and its translocator, as well as the [4Fe–4S] cluster-regulated transport mechanism of oligopeptide permeases found in bacteria.

Precise protein synthesis is achieved by tRNA modifications. Here the authors revealed that modified cytidines in tRNA^Ile use their long side chains to make additional interactions with mRNA for stable tRNA binding on the ribosome.

Rybak and Gagnon elucidate the mechanism of AUG codon avoidance by the minor isoleucine tRNA in Escherichia coli. The lysidinylated C34 in the anticodon loop of tRNA^Ile weakens interactions with the mRNA and destabilizes the EF-Tu ternary complex.

Transcription of toxin–antitoxin modules is regulated by conditional cooperativity, where the toxin enables or disrupts antitoxin-driven repression. Here, the authors solve the structural basis for the conditional cooperativity of Salmonella TacAT3.