Research articles

This study presents the crystal structure of a Fas-FADD complex, a central feature of the so-called death inducing signalling complex. The structure reveals a new mode of death ___domain interactions that allows four FADD and four Fas proteins in one complex.

Intrinsically photosensitive retinal ganglion cells sense and transmit light information to brain centres that control non-image-forming visual functions, such as the pupillary light reflex and circadian photoentrainment. This paper describes the biophysical properties of these melanopsin-containing cells. It is found that single-photons of light are sufficient to elicit large and prolonged responses.

This paper shows that Desulfitobacterium hafniense pyrrolysyl-tRNA synthetase–tRNA^Pyl is an orthogonal pair in vivo and in vitro. The structure of the co-complex reveals the distinct interactions of the protein and tRNA that distinguish this pair from those which function with the twenty standard amino acids.

The CBM complex has a key role in transducing signals from the antigen receptors in T and B cells to the transcription factor NF-κB during lymphocyte activation. Casein kinase 1α (CK1α) is shown to regulate the CBM complex in two opposing ways, first promoting and then subsequently terminating receptor-induced NF-κB activity and lymphocyte activation.

Here, subdiffraction-resolution STED fluorescence microscopy is used to detect the diffusion of single lipids or GPI-anchored proteins on the plasma membrane of a living cell. Tuning the probing spot area ∼70-fold below that of a confocal microscope reveals that unlike phosphoglycerolipids, sphingolipids and GPI-anchored proteins are trapped for ∼10 ms in cholesterol-mediated complexes within <20 nm space.

In vertebrates and other deuterostomes, the molecular pathway that leads to asymmetry utilizes the signalling molecule Nodal, a member of the TGF-β superfamily. But no orthologues of Nodal have been found in the other two great groups of bilaterians. This paper finds orthologues of nodal and one of its targets, Pitx, in two species of snail, and show that loss of nodal disrupts shell coiling.

Nuclear pore complexes (NPCs) serve as gateways between the nucleus and cytoplasm and allow only the transport of selected macromolecules across the nuclear envelope. NPCs are comprised of a scaffold that anchors proteins called FG-nucleoporins, which contain disordered regions that line the inner surface of the pore and extend into the lumen. This study reports the design of an artificial membrane that functions as a selective filter in allowing efficient passage of transport factors and transport factor carrying cargo that specifically bind to FG-nucleoporins.

This paper generates an iPS cell line from patients with spinal muscular atrophy, an autosomal recessive genetic disorder that is one of the most common inherited forms of neurological disease in children.

The chlorophyll biosynthetic enzyme NADPH:protochlorophyllide oxidoreductase, which catalyses a light-driven reaction involving hydride and proton transfers is examined. It is determined that prior excitation of the enzyme–substrate complex with a laser pulse induces a more favourable conformation of the active site and increases the catalytic efficiency of the coupled hydride and proton transfer reactions. Spectral changes in the mid-infrared after the absorption of one photon reveal significant conformational changes in the enzyme.

This study presents a global analysis of seafloor roughness derived from marine gravity data and finds that residual roughness anomalies remain over large swaths of ocean floor. The Atlantic ocean floor that formed over mantle previously overlain by the Pangaea supercontinent displays anomalously low roughness, and attribute this observation to a sub-Pangaean supercontinental mantle temperature anomaly leading to slightly thicker than normal Atlantic crust. In contrast, ocean crust formed above Pacific superswells is not associated with basement roughness anomalies.

This paper reports the discovery of a water maser at redshift 2.64 in the dust- and gas-rich gravitationally lensed type-1 quasar MG J0414+0534. Using the locally determined luminosity function, the probability of finding a maser this luminous associated with any single active galaxy is 10⁻⁶, leading to the conclusion that the volume densities and luminosities of masers are higher at that epoch.

When damaged DNA is replicated, gaps can be left behind in the replicated DNA. Two processes, recombinational repair or post-replication repair (PRR), were thought to act independently in gap filling. This study defines how the error-free branch of PRR is involved in lesion bypass and finds that when the replicative clamp PCNA is SUMO modified, Rad18 and Rad5 are able to promote polyubiquitination of PCNA.

A new family of superconductors containing layers of iron arsenide has attracted considerable interest because of their high transition temperatures and similarities with the high-T_c copper oxide superconductors. This paper reports inelastic neutron scattering observations of a magnetic resonance below T_c in Ba_0.6K_0.4Fe₂As₂, demonstrating that the superconducting energy gap has unconventional symmetry.

During clathrin-mediated endocytosis, cargo proteins are recognized by clathrin adaptors. The clathrin adaptor AP2 recognizes two major classes of endocytic motifs, including an acidic dileucine motif. This study presents the crystal structure of AP2 in complex with the diceucine motif of a cargo protein, thereby revealing the mechanism of cargo–adaptor recognition.

A proteomics study unveils a large collection of proteins that get reversibly palmitoylated in response to neuronal activity — the neuronal palmitoyl-proteome. In particular, this study focuses on the discovery of a brain-specific isoform of the small GTPase Cdc42, whose unexpected palmitoylation specifically affects dendritic spine morphogenesis in response to neuronal activity. These findings identify palmitoylation as a key modifiable signal on many synapse-enriched proteins that contribute to activity-driven changes in synapse morphology and function.

Geometric frustration arises when lattice structure prevents energetic interactions between neighbouring particles to be minimized, leading to complex phases of matter. This paper reports a simple geometrically frustrated system composed of closely packed colloidal spheres confined between parallel walls. Because the diameter of the spheres is tunable, the system provides a unique means to directly visualize the dynamics of frustration, thermal excitations and defects.

The structure of a thermophilic Ago protein bound to a duplex nucleic acid that mimics the interaction of the single-strand of the small RNA and the target mRNA has been solved. This structure reveals the conformational changes that are necessary to accommodate the target, and the changes that occur in the vicinity of the site of cleavage.