Proteomic analysis of the mammalian nuclear pore complex

As the sole site of nucleocytoplasmic transport, the nuclear pore complex (NPC) has a vital cellular role. Nonetheless, much remains to be learned about many fundamental aspects of NPC function. To further understand the structure and function of the mammalian NPC, we have completed a proteomic analysis to identify and classify all of its protein components. We used mass spectrometry to identify all proteins present in a biochemically purified NPC fraction. Based on previous characterization, sequence homology, and subcellular localization, 29 of these proteins were classified as nucleoporins, and a further 18 were classified as NPC-associated proteins. Among the 29 nucleoporins were six previously undiscovered nucleoporins and a novel family of WD repeat nucleoporins. One of these WD repeat nucleoporins is ALADIN, the gene mutated in triple-A (or Allgrove) syndrome. Our analysis defines the proteome of the mammalian NPC for the first time and paves the way for a more detailed characterization of NPC structure and function

Pore timing:the evolutionary origins of the nucleus and nuclear pore complex

The name “eukaryote” is derived from Greek, meaning “true kernel”, and describes the domain of organisms whose cells have a nucleus. The nucleus is thus the defining feature of eukaryotes and distinguishes them from prokaryotes (Archaea and Bacteria), whose cells lack nuclei. Despite this, we discuss the intriguing possibility that organisms on the path from the first eukaryotic common ancestor to the last common ancestor of all eukaryotes did not possess a nucleus at all—at least not in a form we would recognize today—and that the nucleus in fact arrived relatively late in the evolution of eukaryotes. The clues to this alternative evolutionary path lie, most of all, in recent discoveries concerning the structure of the nuclear pore complex. We discuss the evidence for such a possibility and how this impacts our views of eukaryote origins and how eukaryotes have diversified subsequent to their last common ancestor

Nucleocytoplasmic transport: a thermodynamic mechanism

The nuclear pore supports molecular communication between cytoplasm and nucleus in eukaryotic cells. Selective transport of proteins is mediated by soluble receptors, whose regulation by the small GTPase Ran leads to cargo accumulation in, or depletion from the nucleus, i.e., nuclear import or nuclear export. We consider the operation of this transport system by a combined analytical and experimental approach. Provocative predictions of a simple model were tested using cell-free nuclei reconstituted in Xenopus egg extract, a system well suited to quantitative studies. We found that accumulation capacity is limited, so that introduction of one import cargo leads to egress of another. Clearly, the pore per se does not determine transport directionality. Moreover, different cargo reach a similar ratio of nuclear to cytoplasmic concentration in steady-state. The model shows that this ratio should in fact be independent of the receptor-cargo affinity, though kinetics may be strongly influenced. Numerical conservation of the system components highlights a conflict between the observations and the popular concept of transport cycles. We suggest that chemical partitioning provides a framework to understand the capacity to generate concentration gradients by equilibration of the receptor-cargo intermediary.Comment: in press at HFSP Journal, vol 3 16 text pages, 1 table, 4 figures, plus Supplementary Material include

GISualization: visualized integration of multiple types of data for knowledge co-production

Urban planning deals with multiple layers of information stemming from concurrent activities and stakeholders intervening in urban development. For a better management of complexity more comprehensiveness and data integration are needed. This study develops an adaptive and iterative mixed-method approach for knowledge production in urban transformation processes. Specific research questions relate to data integration from different sources and facilitation of co-production of knowledge beyond triangulation. A new multi-layer framework, GISualization, has been developed in the context of a research project exploring compact city qualities. The framework is structured through five data layers, representing different methods for data collection and different grades of complexity, richness and interpretation: basic statistics; advanced statistics; exogenous quali-quantitative descriptions; exogenous qualitative descriptions; and endogenous qualitative descriptions. Thus, data stem from both quantitative and qualitative sources. Our study has proven that GISualization is a methodological framework that enables analysis and visualization of complex data in a rich format. The approach is closely related to analytical eclecticism and abductivity. It embodies a collaborative communication platform that provides a language to navigate between heterogeneous data, information and methods. The GISualization framework opens up for broader stakeholder involvement and community participation extending research into the domain of transdisciplinary knowledge production

Can Charisma Be Taught? Tests of Two Interventions

We tested whether we could teach individuals to behave more charismatically, andwhether changes in charisma affected leader outcomes. In Study 1, a mixed-design fieldexperiment, we randomly assigned 34 middle-level managers to a control or anexperimental group. Three months later, we reassessed the managers using theircoworker ratings (Time 1 raters = 343; Time 2 raters = 321). In Study 2, a within-subjectslaboratory experiment, we videotaped 41 MBA participants giving a speech. We thentaught them how to behave more charismatically, and they redelivered the speech6 weeks later. Independent assessors (n = 135) rated the speeches. Results from thestudies indicated that the training had significant effects on ratings of leader charisma(mean D = .62) and that charisma had significant effects on ratings of leaderprototypicality and emergence...............................................................................................................................

Political Branding: The Tea Party and Its Use of Participation Branding

The emergence of the Tea Party movement in 2009 witnessed the surfacing of a populist, anti-Obama libertarian mobilization within the United States. The Tea Party, a movement that brought together a number of disparate groups—some new, some established—utilized participation branding where the consumer attributed the movement its own identity and brand. Its consumer-facing approach, lack of one single leader, and lack of a detailed party platform, in combination with its impact on the 2010 election races in America, earmarks it as a contemporary and unconventional brand phenomenon worthy of investigation. Copyright © Taylor & Francis Group, LLC