The mitotic-spindle-associated protein astrin is essential for progression through mitosis

Astrin is a mitotic-spindle-associated protein expressed in most human cell lines and tissues. However, its functions in spindle organization and mitosis have not yet been determined. Sequence analysis revealed that astrin has an N-terminal globular domain and an extended coiled-coil domain. Recombinant astrin was purified and characterized by CD spectroscopy and electron microscopy. Astrin showed parallel dimers with head- stalk structures reminiscent of motor proteins, although no sequence similarities to known motor proteins were found. In physiological buffers, astrin dimers oligomerized via their globular head domains and formed aster-like structures. Silencing of astrin in HeLa cells by RNA interference resulted in growth arrest, with formation of multipolar and highly disordered spindles. Chromosomes did not congress to the spindle equator and remained dispersed. Cells depleted of astrin were normal during interphase but were unable to progress through mitosis and finally ended in apoptotic cell death. Possible functions of astrin in mitotic spindle organization are discussed

Defining desmosomal plakophilin-3 interactions

Plakophilin 3 (PKP3) is a recently described armadillo protein of the desmosomal plaque, which is synthesized in simple and stratified epithelia. We investigated the localization pattern of endogenous and exogenous PKP3 and fragments thereof. The desmosomal binding properties of PKP3 were determined using yeast two-hybrid, coimmunoprecipitation and colocalization experiments. To this end, novel mouse anti-PKP3 mAbs were generated. We found that PKP3 binds all three desmogleins, desmocollin (Dsc) 3a and -3b, and possibly also Dsc1a and -2a. As such, this is the first protein interaction ever observed with a Dsc-b isoform. Moreover, we determined that PKP3 interacts with plakoglobin, desmoplakin (DP) and the epithelial keratin 18. Evidence was found for the presence of at least two DP–PKP3 interaction sites. This finding might explain how lateral DP–PKP interactions are established in the upper layers of stratified epithelia, increasing the size of the desmosome and the number of anchoring points available for keratins. Together, these results show that PKP3, whose epithelial and epidermal desmosomal expression pattern and protein interaction repertoire are broader than those of PKP1 and -2, is a unique multiprotein binding element in the basic architecture of a vast majority of epithelial desmosomes

Tectonic deformation of the Andes and the configuration of the subducted slab in central Peru: Results from a micro-seismic experiment

The vast majority of the microearthquakes recorded occurred to the east: on the Huaytapallana fault in the Eastern Cordillera or in the western margin of the sub-Andes. The sub-Andes appear to be the physiographic province subjected to the most intense seismic deformation. Focal depths for the crustal events here are as deep as 50 km, and the fault plane solutions, show thrust faulting on steep planes oriented roughly north-south. The Huaytapallana fault in the Cordillera Oriental also shows relatively high seismicity along a northeast-southwest trend that agrees with the fault scarp and the east dipping nodal plane of two large earthquakes that occurred on this fault in 1969. The recorded microearthquakes of intermediate depth show a flat seismic zone about 25 km thick at a depth of about 100 km. This agrees with the suggestion that beneath Peru the slab first dips at an angle of 30 deg to a depth of 100 km and then flattens following a quasi-horizontal trajectory. Fault plane solutions of intermediate depth microearthquakes have horizontal T axes oriented east-west

The configuration of the seismic zone and the downgoing slab in southern Peru

Using data from temporary networks of portable seismographs in southern Peru, we located 888 shallow and intermediate depth events near a proposed discontinuity in the seismic zone there. These events reveal a prominent contortion, instead of a discontinuity, that trends approximately N80°E, parallel to the direction of relative plate motion. North of about 15°S, the seismic zone beneath Peru is nearly horizontal, but south of about 15.5°S, it dips at about 25°. Volcanoes lie above the more steeply dipping zone where earthquakes occur between 120 and 140 km, and the volcanic line in southern Peru stops abruptly at the contortion

The Molecular Evolution of the p120-Catenin Subfamily and Its Functional Associations

p120-catenin (p120) is the prototypical member of a subclass of armadillo-related proteins that includes δ-catenin/NPRAP, ARVCF, p0071, and the more distantly related plakophilins 1–3. In vertebrates, p120 is essential in regulating surface expression and stability of all classical cadherins, and directly interacts with Kaiso, a BTB/ZF family transcription factor.To clarify functional relationships between these proteins and how they relate to the classical cadherins, we have examined the proteomes of 14 diverse vertebrate and metazoan species. The data reveal a single ancient δ-catenin-like p120 family member present in the earliest metazoans and conserved throughout metazoan evolution. This single p120 family protein is present in all protostomes, and in certain early-branching chordate lineages. Phylogenetic analyses suggest that gene duplication and functional diversification into “p120-like” and “δ-catenin-like” proteins occurred in the urochordate-vertebrate ancestor. Additional gene duplications during early vertebrate evolution gave rise to the seven vertebrate p120 family members. Kaiso family members (i.e., Kaiso, ZBTB38 and ZBTB4) are found only in vertebrates, their origin following that of the p120-like gene lineage and coinciding with the evolution of vertebrate-specific mechanisms of epigenetic gene regulation by CpG island methylation.The p120 protein family evolved from a common δ-catenin-like ancestor present in all metazoans. Through several rounds of gene duplication and diversification, however, p120 evolved in vertebrates into an essential, ubiquitously expressed protein, whereas loss of the more selectively expressed δ-catenin, p0071 and ARVCF are tolerated in most species. Together with phylogenetic studies of the vertebrate cadherins, our data suggest that the p120-like and δ-catenin-like genes co-evolved separately with non-neural (E- and P-cadherin) and neural (N- and R-cadherin) cadherin lineages, respectively. The expansion of p120 relative to δ-catenin during vertebrate evolution may reflect the pivotal and largely disproportionate role of the non-neural cadherins with respect to evolution of the wide range of somatic morphology present in vertebrates today

“I’m only a dog!” : the Rwandan genocide, dehumanisation and the graphic novel

Graphic novels written in response to the 1994 Rwandan genocide do not confine their depictions of traumatic violence to humans, but extend their coverage to show how the genocide impacted on animals and the environment. Through analysis of the presentation of people and their relationships with other species across a range of graphic narratives, this article shows how animal imagery was used to justify inhumane actions during the genocide, and argues that representations of animals remain central to the recuperation processes in a post-genocide context too. Whilst novels and films that respond to the genocide have been the focus of scholarly work (Dauge-Roth, 2010), the graphic novel has yet to receive substantial critical attention. This article therefore unlocks the archive of French-, Dutch- and English-language graphic narratives written in response to the genocide by providing the first in-depth, comparative analysis of their animal representations. It draws on recent methodological approaches derived from philosophy (Derrida, [2008] trans. 2009), postcolonial ecocriticism (Huggan and Tiffin, 2010) and postcolonial trauma theory (Craps, 2012) in order show how human-centred strategies for recovery, and associated symbolic orders that forcefully position the animal outside of human law, continue to engender unequal and potentially violent relationships between humans, and humans and other species. In this way, graphic narratives that gesture towards more equitable relationships between humans, animals and the environment can be seen to support the processes of recovery and reconciliation in post-genocide Rwanda

The evolutionary history of the catenin gene family during metazoan evolution

<p>Abstract</p> <p>Background</p> <p>Catenin is a gene family composed of three subfamilies; p120, beta and alpha. Beta and p120 are homologous subfamilies based on sequence and structural comparisons, and are members of the armadillo repeat protein superfamily. Alpha does not appear to be homologous to either beta or p120 based on the lack of sequence and structural similarity, and the alpha subfamily belongs to the vinculin superfamily. Catenins link the transmembrane protein cadherin to the cytoskeleton and thus function in cell-cell adhesion. To date, only the beta subfamily has been evolutionarily analyzed and experimentally studied for its functions in signaling pathways, development and human diseases such as cancer. We present a detailed evolutionary study of the whole catenin family to provide a better understanding of how this family has evolved in metazoans, and by extension, the evolution of cell-cell adhesion.</p> <p>Results</p> <p>All three catenin subfamilies have been detected in metazoans used in the present study by searching public databases and applying species-specific BLAST searches. Two monophyletic clades are formed between beta and p120 subfamilies using Bayesian phylogenetic inference. Phylogenetic analyses also reveal an array of duplication events throughout metazoan history. Furthermore, numerous annotation issues for the catenin family have been detected by our computational analyses.</p> <p>Conclusions</p> <p>Delta2/ARVCF catenin in the p120 subfamily, beta catenin in the beta subfamily, and alpha2 catenin in the alpha subfamily are present in all metazoans analyzed. This implies that the last common ancestor of metazoans had these three catenin subfamilies. However, not all members within each subfamily were detected in all metazoan species. Each subfamily has undergone duplications at different levels (species-specific, subphylum-specific or phylum-specific) and to different extents (in the case of the number of homologs). Extensive annotation problems have been resolved in each of the three catenin subfamilies. This resolution provides a more coherent description of catenin evolution.</p

The sulfur pathway and diagnosis of sulfate depletion in grapevine

Sulfur is an essential nutrient to all plant species. Plants assimilate sulfur in a well-described pathway, which has been taken up by roots. Regulatory mech- anism has been the subject of many research papers. However, recent studies highlighted differences between crop plants and the model plant Arabidopsis thaliana. Our work focuses on the identification of genes involved in the sulfur metabolism in the Vitis vinifera genome, and their response to sulfur deficiency and other abiotic stress endured by grapevine in the field, namely water stress. Here, we describe the identification and brief characterization of the first assimilation enzymes involved in the sulfur pathway, the enzyme responsible for sulfur activa- tion, ATP sulfurylase (ATPS), and the two enzymes that reduce sulfate to sulfide, Adenosine 50-phosphosulate reductase (APR) and Sulfite reductase (SiR). A reduc- tion was observed in the number of ATPS and APR isoforms identified in V. vinifera genome when compared to A. thaliana or Glycine max genomes. Two ATPS isoforms were present in the Vitis genome, of which only ATPS1 transcript was detected in the tested tissues, and one APR isoform, suggesting an absence of redundancy in the role of both enzymes. ATPS1, APR and SiR transcript level was up-regulated in response to 2 days exposure to sulfur deficiency in V. vinifera cell cultures, which was completely reversed by the addition of GSH to the culture medium. Apparently, oxidative stress triggered GSH has a pivotal role in the regulation of ATPS1, APR and SiR transcription level, since their up-regulation was observed in mRNA from field grapevine berries under water stress, which is known to induce oxidative stress.info:eu-repo/semantics/publishedVersio