The Biochemistry, Ultrastructure, and Subunit Assembly Mechanism of AMPA Receptors

The AMPA-type ionotropic glutamate receptors (AMPA-Rs) are tetrameric ligand-gated ion channels that play crucial roles in synaptic transmission and plasticity. Our knowledge about the ultrastructure and subunit assembly mechanisms of intact AMPA-Rs was very limited. However, the new studies using single particle EM and X-ray crystallography are revealing important insights. For example, the tetrameric crystal structure of the GluA2cryst construct provided the atomic view of the intact receptor. In addition, the single particle EM structures of the subunit assembly intermediates revealed the conformational requirement for the dimer-to-tetramer transition during the maturation of AMPA-Rs. These new data in the field provide new models and interpretations. In the brain, the native AMPA-R complexes contain auxiliary subunits that influence subunit assembly, gating, and trafficking of the AMPA-Rs. Understanding the mechanisms of the auxiliary subunits will become increasingly important to precisely describe the function of AMPA-Rs in the brain. The AMPA-R proteomics studies continuously reveal a previously unexpected degree of molecular heterogeneity of the complex. Because the AMPA-Rs are important drug targets for treating various neurological and psychiatric diseases, it is likely that these new native complexes will require detailed mechanistic analysis in the future. The current ultrastructural data on the receptors and the receptor-expressing stable cell lines that were developed during the course of these studies are useful resources for high throughput drug screening and further drug designing. Moreover, we are getting closer to understanding the precise mechanisms of AMPA-R-mediated synaptic plasticity

Sequence at the 3' end of globin mRNA shows homology with immunoglobulin light chain mRNA.

No chamado processo para regimes democráticos na América Latina, embora tenha se constatado avanços importantes do ponto de vista formal-institucional, numa perspectiva mais ampla, que leve em conta conquistas sociais, o resultado tem sido modesto. Vive-se, nesta região, presentemente, uma assimetria entre uma legitimidade jurídica concomitantemente com a ausência de uma legitimidade social. Tal situação exige reflexões teóricas que vão além da democracia minimalista e considerem a democracia como um estado social, uma ética e um modo de vida. Com base nesses aspectos, este artigo analisa a atual situação da América Latina do ponto de vista da cultura política existente, para, num segundo momento, propor um modelo compreensivo e empírico, com base em pesquisas de opinião realizadas em 2005, 2009 e 2010, em três cidades latino-americanas, enfatizando conceitos tais como: desenvolvimento sustentável, capital social e empoderamento. Os resultados mostram que existem estoques latentes que, se ativados adequadamente, poderiam contribuir para melhorar a democracia nesta região.The transition process to democratic regimes in Latin America, although important advances can be observed in the formal-institutional arena, from a more wide spectrum that take into account social conquests, the results have been modest. Presently, this region lives an asymmetry between a legal legitimacy concomitant with the absence of social legitimacy. In this context it becomes necessary to go beyond minimalist democratic conceptions to conceptualizations that consider democracy as a social state, an ethic and a way of life. Based upon these elements this paper analyzes the present situation of Latin American from the political culture point of view, and subsequently proposes a comprehensive and empirical model with data from surveys conducted in three Latin American cities in 2005, 2009 and 2010, emphasizing the concepts of sustainable development, social capital and empowerment. The results indicate the existence of latent stocks of these concepts that if activated correctly could contribute to improve the quality of democracy