Research articles

The activation and coordination of phosphatase activity is important during mitotic exit; here, a mitotic phosphatase relay is described in fission yeast between the two major phosphatases, PP1 and PP2A, a mode of regulation that may be a feature of signalling networks across eukaryotes.

It has been traditionally assumed that the heat released during a single enzymatic catalytic event does not perturb the enzyme in any way; however, here single-molecule fluorescence correlation spectroscopy is used to show that, for enzymes that catalyse chemical reactions with large reaction enthalpies, the heat released at the protein's active site during catalysis transiently displaces the protein's centre-of-mass, essentially giving rise to a recoil effect that propels the enzyme.

This study tracks dragonfly head and body movements during high-velocity and high-precision prey-capture flights, and shows that the dragonfly uses predictive internal models and reactive control to build an interception trajectory that complies with biomechanical constraints.

Studies of gene-expression levels in embryos of Caenorhabditis elegans and of other phyla reveal the timing and location of expression of all genes and support a model in which the endoderm program dates back to the origin of multicellularity while the ectoderm originated as a secondary germ layer freed from ancestral feeding functions.

The forced expression of key transcription factors can induce somatic cells to acquire pluripotency characteristics; here high levels of reprogramming factors are used to induce mouse embryonic fibroblasts to a stable alternative pluripotent state with low intercellular adhesion.

A tissue with many of the defining features of vertebrate cellular cartilage is shown to form transiently in larvae of the invertebrate chordate amphioxus, indicating that the origin of the vertebrate head skeleton depended not on evolution of a new skeletal tissue, as is commonly thought, but on the spread of this tissue throughout the head.

Wind tunnel experiments designed to simulate the conditions on Saturn’s moon Titan yield threshold wind speeds for particle saltation higher than those predicted by models derived from simulations of terrestrial-planet conditions; the results can be reconciled by modifying the models to take into account the low ratio of particle density to fluid density on Titan.

Somatic TP53 mutations are highly prevalent in therapy-related acute myeloid leukaemia and myelodysplastic syndrome, which arise as complications of cytotoxic chemotherapy or radiotherapy; although it was believed that these TP53 mutations are directly induced by cytotoxic therapy, new data indicate that they predate cytotoxic therapy and that haematopoietic progenitors harbouring these pre-existing mutations may selectively expand after exposure to chemotherapy or radiotherapy.

How socially transmitted behaviours spread and persist is shown in a wild animal population, revealing an effect of social conformity.

The deubiquitinase enzyme DUBA is shown to act as a negative regulator of interleukin-17A (IL-17A) in T_H17 cells; DUBA interacts with and stabilizes the ubiquitin ligase UBR5, which in turn targets RORγt for degradation in the proteaseome, thus limiting IL-17A production.

Using human bladder cancer xenograft models, a new mechanism involving an active proliferative response of cancer stem cells to chemotherapy-induced damage is shown, driven by prostaglandin E₂ (PGE₂) release in a manner similar to PGE₂-induced wound repair; pharmacological inhibition of the PGE₂/COX2 axis by celecoxib attenuates chemoresistance, suggesting a possible adjunctive therapy for bladder carcinomas.

Femtosecond X-ray diffraction and ab initio density functional theory calculations are used to determine the crystal structure of YBa₂Cu₃O_6.5 undergoing optically driven, nonlinear lattice excitation above the transition temperature of 52 kelvin, under which conditions the electronic structure of the material changes in such a way as to favour superconductivity.

Here the structure of the membrane protein complex sodium-translocating NADH:quinone oxidoreductase (Na⁺-NQR) is described; as Na⁺-NQR is a component of the respiratory chain of various bacteria, including pathogenic ones, this structure may serve as the basis for the development of new antibiotics.

A technique based on compressed imaging with a streak camera is reported that can videotape transient events in two dimensions with temporal resolution down to tens of picoseconds, and its usefulness is demonstrated using single laser shots applied to a variety of physical phenomena.

To determine the origin of adult tissue-resident macrophages, a mouse lineage tracing study has revealed that these cells derive from erythro-myeloid progenitors in the yolk sac that are distinct from fetal and adult haematopoietic stem cells.

El Niño events can transfer subsurface heat to the eastern North Pacific with a delay of several months, causing the intensification of tropical cyclones; the mechanism may lead to insights into past variations in tropical cyclone intensity and enhance seasonal predictions.

Argon and luminescence dating of fossil shell infills from Trinil in Java, where Homo erectus lived, reveals that the hominin-bearing deposits are younger than previously thought; perforated shells, a shell tool and an engraved shell indicate that Homo erectus ate freshwater mussels, used their shells as tools and was able to create abstract engravings.

X-ray structures of the human TRAAK mechanosensitive potassium channel reveal how build-up of tension in the lipid membrane can convert the channel from a non-conducting wedge shape associated with an inserted lipid acyl chain that blocks the pore to an expanded cross-sectional shape that prevents lipid entry and thus permits ion conduction.

The African Genome Variation Project contains the whole-genome sequences of 320 individuals and dense genotypes on 1,481 individuals from sub-Saharan Africa; it enables the design and interpretation of genomic studies, with implications for finding disease loci and clues to human origins.

Regeneration and plasticity after spinal cord injury are limited by inhibitory proteoglycans; here, modulation of a receptor for proteoglycans in rats is shown to lead to functional recovery after injury.