1,721,003 research outputs found
Computational approaches for protein function prediction: a combined strategy from multiple sequence alignment to molecular docking-based virtual screening
No full textA MOLECULAR EXPLANATION OF SLC25A1 DEFICIENCY RESULTING IN AGENESIS OF CORPUS CALLOSUM AND OPTIC NERVE HYPOPLASIA
No full textMitochondrial carriers (MCs) form a large family of nuclear-encoded transporters embedded in the inner mitochondrial membrane and in a few cases in other organelle membranes (Palmieri, 2013). The members of this superfamily are widespread in eukaryotes and involved in numerous metabolic pathways and cell functions. They can be easily recognized by their striking sequence features, i.e., a tripartite structure, six transmembrane α-helices and a 3-fold repeated signature motifs. Members of the family vary greatly in the nature and size of their transported substrates, modes of transport (i.e., uniport, symport or antiport) and driving forces, although the molecular mechanism of substrate translocation may be basically the same. In recent years mutations in the MC genes have been shown to be responsible for 11 diseases (Palmieri, 2013), highlighting the important role of MCs in metabolism. MC impairing mutations affect three main regions crucial for substrate translocation. A first group of mutations affects MC conformational changes and locates at PG levels or at the aromatic belts (Pierri et al., 2013). A second group of mutations affects substrate specificity and locates at the common substrate binding site (Robinson et al., 2008) and at the substrate binding area (Pierri et al., 2013). A further group of mutations locate at residues of the m-/c-gates (Palmieri et al., 2013; Robinson et al., 2008) and at residues of the m-gate area (Pierri et al. 2013). For this last group of mutations, it appears difficult to establish if the impaired function is due to the lack of substrate specificity (or substrate recognition) or to the wrong triggering of conformational changes. Two mutations, one at the PG level 1 and one at the common substrate binding site, impairing citrate translocation within SLC25A1_CTP protein are presented. The two mutations are found to be responsible of agenesis of corpus callosum and optic nerve hypoplasia (Edvardson et al., 2013).
References
1. Palmieri F. The mitochondrial transporter family SLC25: identification, properties and physiopathology. Mol Aspects Med. 2013;34:465.
2. Pierri CL, Palmieri F, De Grassi A. Single-nucleotide evolution quantifies the importance of each site along the structure of mitochondrial carriers. Cell Mol Life Sci. 2013.
3. Robinson AJ, Overy C, Kunji ER. The mechanism of transport by mitochondrial carriers based on analysis of symmetry. Proc Natl Acad Sci U S A. 2008;105:17766.
4. Edvardson S, Porcelli V, Jalas C, Soiferman D, Kellner Y, Shaag A, Korman SH, Pierri CL, Scarcia P, Fraenkel ND, Segel R, Schechter A, Frumkin A, Pines O, Saada A, Palmieri L, Elpeleg O. Agenesis of corpus callosum and optic nerve hypoplasia due to mutations in SLC25A1 encoding the mitochondrial citrate transporter. J Med Genet. 2013;50:240
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The mitochondrial aspartate/glutamate carrier AGC1 and calcium homeostasis: Physiological links and abnormalities in autism
No full textAutism spectrum disorder (ASD) is a severe, complex neurodevelopmental disorder characterized by impairments in reciprocal social interaction and communication, and restricted and stereotyped patterns of interests and behaviors. Recent evidence has unveiled an important role for calcium (Ca 2+) signaling in the pathogenesis of ASD. Post-mortem studies of autistic brains have pointed toward abnormalities in mitochondrial function as possible downstream consequences of altered Ca2+ signaling, abnormal synapse formation, and dysreactive immunity. SLC25A12, an ASD susceptibility gene, encodes the Ca2+-regulated mitochondrial aspartate-glutamate carrier, isoform 1 (AGC1). AGC1 is an important component of the malate/aspartate shuttle, a crucial system supporting oxidative phosphorylation and adenosine triphosphate (ATP) production. Here, we review the physiological roles of AGC1, its links to calcium homeostasis, and its involvement in autism pathogenesis. © 2011 Springer Science+Business Media, LLC
The mitochondrial aspartate/glutamate carrier AGC1 and calcium homeostasis: physiological links and abnormalities in autism
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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