Research articles

In neurons, GABA_A receptors mediate feed-forward inhibition by shunting excitatory currents and hyperpolarizing neurons. Here, the authors show that the hyperpolarization-activated mixed cation current is critical for determining the resting membrane potential and reversal potential for GABA_A-mediated currents.

Cathepsin L mediates proteolysis of the histone H3 tail and is a factor in cell-cycle progression and cellular differentiation. Adams-Cioabaet al. report crystal structures of an inactive mutant of the protease complexed with substrate peptides, and find that it is highly accommodating of modified substrates.

Clathrates are minerals with cage-like structural voids that can be filled by guest species; three types are plausible but only one has been observed in nature. Mommaet al. have discovered the remaining two types in Japanese marine sediments, and determined their structural similarity to natural gas hydrates.

Trees of the genusEucalyptusdominate the flora in Australia and can undergo resprouting after fire. Here, fossils and DNA of eucalypts reveal that the resprouting feature of the trees can be linked to the evolution of fire biomes, and that this likely began 60 million years ago.

Leptosphaeria maculans is a plant pathogen that causes stem canker of oilseed rape. Rouxel et al. sequence and describe the key features of the L. maculansgenome, including partitioning into AT-rich blocks that are enriched in effector genes and transposable elements affected by repeat-induced point mutation.

The interiors of outer solar planets are believed to contain water–methane mixtures that are subject to extreme pressures. Lee and Scandolo use molecular dynamics simulations to show that at high pressures there can be enhanced mixing and ionization, with consequences for the origin of the planetary magnetic field.

Proteorhodopsin is used by prokaryotes to generate energy from light. In this study, the authors describe a prokaryote-to-eukaryote horizontal gene transfer of a bacterial proteorhodopsin gene to dinoflagellates, suggesting that these eukaryotes can also use proteorhodopsin to obtain light and produce energy.

Interface effects in complex oxides could have interesting technological applications. Ariandoet al. demonstrate electronic phase separation and rich physics at a complex oxide interface between the two non-magnetic insulators LaAlO₃ and SrTiO₃.

The nonlocality of a quantum state is often difficult to predict. Here, Cavalcanti and colleagues devise a method based on networks that makes this characterization much easier, revealing that the nonlocality of a quantum state depends on the context of the measurement.

Post-translational modifications are important in regulating protein function and turnover, and Ufm1 is part of a recently identified protein modification system. In this study, the authors show that Uba5, a component of the Ufm1 system, is important for regulating haematopoiesis and the differentiation of erythroid cells.

The central nervous system contains glial cells, which have been shown to have an important role in neuronal survival. Haradaet al. use transgenic mouse models to show that TrkB, a receptor for the growth factor brain-derived neurotrophic factor, is required for retinal Müller glial cells to provide neuroprotection and regeneration.

Rad23 accompanies ubiquitinated substrates to the proteasome for destruction but manages to avoid degradation. In this study, Fishbainet al.show that Rad23 escapes because it lacks an effective initiation region; therefore, the proteasome is unable to engage the protein and unfold it.

The gut is populated by a myriad of microorganisms and how the immune system tolerates their presence is of great interest. Here, by studying colon morphology in multiple knockout mice, the authors demonstrate a potential role for prostaglandin E2 and SOCS1 in mediating immune tolerance.

Rad23 and Dsk2 bind polyubiquitylated proteins and escort them to the proteasome for destruction. In this study, Heinenet al.investigate the molecular mechanisms that protect the C-terminal UBA domains of Rad23 and Dsk2 from proteasomal destruction.

Predicting ecological impacts of climate change is complicated, because key biological parameters are unknown for future conditions. Using a mechanistic energy budget model to relate sea ice to polar bear reproduction, Molnáret al.predict decreases in litter size with anticipated changes in sea ice.

Hedgehog signalling gradients are required for proper wing formation inDrosophila, and Hedgehog is known to regulate the cubitus interruptus transcription factor. Here, the authors show that the COP9 signalosome has a critical role in translating a Hedgehog gradient into a cubitus interruptus gradient.

Inherited congenital heart defects are prevalent in the human population, but the molecular mechanisms are poorly understood. In this article, deficiency in the chromatin remodelling factor, Brg1, is shown to alter cardiac development in both mouse and zebrafish laboratory models.

Until now, invisibility cloaks have only covered a region of a few wavelengths because of their nanostructured materials. Chenet al.describe a macroscopic cloak, made of calcite birefringent crystals, which works for a specific polarization at visible wavelengths.

The origin of the highest energy cosmic rays is still unknown. Here, Chakraborti and colleagues show that a recently discovered sub-population of type Ibc supernovae with mildly relativistic outflows can satisfy all required characteristics for an ultra-high-energy cosmic ray source.

Efficient memory systems are vital for the development of quantum communications technologies. Hosseini and colleagues describe an optical memory based on warm rubidium vapour that achieves 87% pulse recall efficiency, illustrating the potential of warm atomic vapour systems for quantum memory.