The RCK Domain of the KtrAB K+ Transporter: Multiple Conformations of an Octameric Ring

SummaryThe KtrAB ion transporter is a complex of the KtrB membrane protein and KtrA, an RCK domain. RCK domains regulate eukaryotic and prokaryotic membrane proteins involved in K+ transport. Conflicting functional models have proposed two different oligomeric arrangements for RCK domains, tetramer versus octamer. Our results for the KtrAB RCK domain clearly show an octamer in solution and in the crystal. We determined the structure of this protein in three different octameric ring conformations that resemble the RCK-domain octamer observed in the MthK potassium channel but show striking differences in size and symmetry. We present experimental evidence for the association between one RCK octameric ring and two KtrB membrane proteins. These results provide insights into the quaternary organization of the KtrAB transporter and its mechanism of activation and show that the RCK-domain octameric ring model is generally applicable to other ion-transport systems

Evolution of the Far-infrared Cloud at Titan's South Pole

A condensate cloud on Titan identified by its 220 cm (sup -1) far-infrared signature continues to undergo seasonal changes at both the north and south poles. In the north the cloud, which extends from 55 North to the pole, has been gradually decreasing in emission intensity since the beginning of the Cassini mission with a half-life of 3.8 years. The cloud in the south did not appear until 2012 but its intensity has increased rapidly, doubling every year. The shape of the cloud at the South Pole is very different from that in the north. Mapping in December 2013 showed that the condensate emission was confined to a ring with a maximum at 80 South. The ring was centered 4 degrees from Titan's pole. The pattern of emission from stratospheric trace gases like nitriles and complex hydrocarbons (mapped in January 2014) was also offset by 4 degrees, but had a central peak at the pole and a secondary maximum in a ring at about 70 South with a minimum at 80 South. The shape of the gas emissions distribution can be explained by abundances that are high at the atmospheric pole and diminish toward the equator, combined with correspondingly increasing temperatures. We discuss possible causes for the condensate ring. The present rapid build up of the condensate cloud at the South Pole is likely to transition to a gradual decline during 2015-16

Going it alone? North Korea’s adaptability as a small power in a changing world

This article uses small states scholarship to map North Korea’s evolution from a post-colonial small state to a system-influencing state due to its nuclear weapons programme. The framework allows for contributions to: (1) The DPRK literature which in some parts has suggested the future collapse of the state, (2) The small states literature that suggests they can only survive if they integrate larger political and/or economic units, (3) The mainstream IR literature and its dominant realist streak that considers great powers and their will as the main drivers in contemporary world politics

Affect is what states make of it: articulating everyday experiences of 9/11

This article considers the politics of affect and official discourses of ‘9/11’. Drawing on the work of William Connolly and others, it is argued that to understand the resonance of dominant constructions of ‘9/11’ it is necessary to revisit their successful incorporation of prevalent American affective experiences of September 11th. To date, this relationship between affect, resonance, and discourse has been underexplored in International Relations. Its investigation offers important empirical insights on resonance, as well as theoretical innovation in connecting established work on narrative and discourse with emerging work on bioculture and affect. To this end, the article introduces a framework for the future analysis of affect, culture and discourse within International Relations. The article concludes, however, that, notwithstanding its importance to resonance, in ‘crisis’ situations such as ‘9/11’, affect is what states make of it

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

What Makes Retirees Happier: A Gradual or 'Cold Turkey' Retirement?

This study explores the factors that affect an individual’s happiness while transitioning into retirement. Recent studies highlight gradual retirement as an attractive option to older workers as they approach full retirement. However, it is not clear whether phasing or cold turkey makes for a happier retirement. Using longitudinal data from the Health and Retirement Study, this study explores what shapes the change in happiness between the last wave of full employment and the first wave of full retirement. Results suggest that what really matters is not the type of transition (gradual retirement or cold turkey), but whether people perceive the transition as chosen or forced