The rockefeller university

Centrosomes are microtubule-organizing centers that facilitate bipolar mitotic spindle assembly and chromosome segregation. Recognizing that centrosome amplification is a common feature of aneuploid cancer cells, we tested whether supernumerary centrosomes are sufficient to drive tumor development. To do this, we constructed and analyzed mice in which centrosome amplification can be induced by a Cre-recombinase-mediated increase in expression of Polo-like kinase 4 (Plk4). Elevated Plk4 in mouse fibroblasts produced supernumerary centrosomes and enhanced the expected mitotic errors, but proliferation continued only after inactivation of the p53 tumor suppressor. Increasing Plk4 levels in mice with functional p53 produced centrosome amplification in liver and skin, but this did not promote spontaneous tumor development in these tissues or enhance the growth of chemically induced skin tumors. In the absence of p53, Plk4 overexpression generated widespread centrosome amplification, but did not drive additional tumors or affect development of the fatal thymic lymphomas that arise in animals lacking p53. We conclude that, independent of p53 status, supernumerary centrosomes are not sufficient to drive tumor formation.

The present study investigated the role of oestrogen receptor (ER) in the ventromedial nucleus of the hypothalamus (VMN), the preoptic area (POA), the medial amygdala (MePD) and the bed nucleus of stria terminalis (BNST) in sociosexual behaviour in female rats. This was conducted in two sets of experiments, with the VMN and POA investigated in the first set, and the MePD and BNST in the second set. The VMN and POA received intense projections from the MePD and BNST. We used a short hairpin RNA encoded within an adeno-associated viral vector directed against the gene for ER to reduce the number of ER in the VMN or POA (first set of experiments) or in the BNST or MePD (second set of experiments) in female rats. The rats were housed in groups of four ovariectomised females and three males in a seminatural environment for 8days. Compared with traditional test set-ups, the seminatural environment provides an arena in which the rats can express their full behavioural repertoire, which allowed us to investigate multiple aspects of social and sexual behaviour in groups of rats. Behavioural observation was performed after oestrogen and progesterone injections. A reduction of ER expression in the VMN or POA diminished the display of paracopulatory behaviours and lordosis responses compared to controls, whereas the lordosis quotient remained unaffected. This suggests that ER in the VMN and POA play an important role in intrinsic sexual motivation. The reduction in ER did not affect the social behaviour of the females, although the males sniffed and pursued the females with reduced ER less than the controls. This suggests that the ER in the VMN and POA is involved in the regulation of sexual attractiveness of females. The ER in the MePD and BNST, on the other hand, plays no role in sociosexual behaviour.

Ever since Stephen Paget's 1889 hypothesis, metastatic organotropism has remained one of cancer's greatest mysteries. Here we demonstrate that exosomes from mouse and human lung-, liver-and brain-tropic tumour cells fuse preferentially with resident cells at their predicted destination, namely lung fibroblasts and epithelial cells, liver Kupffer cells and brain endothelial cells. We show that tumour-derived exosomes uptaken by organ-specific cells prepare the pre-metastatic niche. Treatment with exosomes from lung-tropic models redirected the metastasis of bone-tropic tumour cells. Exosome proteomics revealed distinct integrin expression patterns, in which the exosomal integrins alpha(6)beta(4) and alpha(6)beta(1) were associated with lung metastasis, while exosomal integrin alpha(v)beta(5) was linked to liver metastasis. Targeting the integrins alpha(6)beta(4) and alpha(v)beta(5) decreased exosome uptake, as well as lung and liver metastasis, respectively. We demonstrate that exosome integrin uptake by resident cells activates Src phosphorylation and pro-inflammatory S100 gene expression. Finally, our clinical data indicate that exosomal integrins could be used to predict organ-specific metastasis.

Ghrelin receptor (GhrR) is a promising drug target because of its central role in energy homeostasis. GhrR, known for high constitutive activity, is thought to display multi-state conformations during activation and signaling. We used genetically encoded unnatural amino acids and bioorthogonal labeling reactions to engineer multiple fluorescent donor-acceptor pairs to probe ligand-directed structural changes in GhrR. We demonstrate how conformational dynamics of a G-protein-coupled receptor can be measured in reconstituted systems.

We report on two families, each with documented consanguinity and two affected with overlapping features of Dandy-Walker malformation, genitourinary abnormalities, intellectual disability, and hearing deficit. This phenotype shares similar findings with many well-known syndromes. However, the clinical findings of this syndrome categorize this as a new syndrome as compared with the phenotype of already established syndromes. Due to parental consanguinity, occurrence in siblings of both genders and the absence of manifestations in obligate carrier parents, an autosomal recessive pattern of inheritance is more likely. The authors believe that these families suggest a novel autosomal recessive cerebello-genital syndrome. Array CGH analyses of an affected did not show pathological deletions or duplications. (c) 2015 Wiley Periodicals, Inc.

Extracellular signal-regulated kinase 1/2 (ERK1/2) plays diverse roles in the central nervous system. Activation of ERK1/2 has been observed in various types of neuronal excitation, including seizure activity in vivo and in vitro. However, studies examining ERK1/2 activity and its substrate phosphorylation in parallel are scarce especially in seizure models. We have been studying the phosphorylation state of the presynaptic protein, synapsin I at ERK1/2-dependent and -independent sites in various types of seizure models and showed that ERK1/2- dependent phosphorylation of synapsin I was indeed under control of ERK1/2 activity in vivo. To further expand our study, here we examined the effects of prolonged seizure activity on ERK1/2 activity and synapsin I phosphorylation by using status epilepticus induced by kainic acid (KA-SE) in rats in vivo. In KA-SE, robust ERK1/2 activation was observed in the hippocampus, a representative limbic structure, with lesser activation in the parietal cortex, a representative no-limbic structure. In contrast, the phosphorylation level of synapsin I at ERK1/2-dependent phospho-site 4/5 was profoundly decreased, the extent of which was much larger in the hippocampus than in the parietal cortex. In addition, phosphorylation at other ERK1/2-independent phospho-sites in synapsin I also showed an even larger decrease. All these changes disappeared after recovery from KA-SE. These results indicate that the phosphorylation state of synapsin I is dynamically regulated by the balance between kinase and phosphatase activities. The contrasting features of robust ERK1/2 activation yet synapsin I dephosphorylation may be indicative of an irreversible pathological outcome of the epileptic state in vivo. (C) 2015 Elsevier B.V. All rights reserved.

CagA is a multifunctional toxin of Helicobacter pylori that is secreted into host epithelial cells by a type IV secretion system. Following host cell translocation, CagA interferes with various host-cell signalling pathways. Most notably this toxin is involved in the disruption of apical-basolateral cell polarity and cell adhesion, as well as in the induction of cell proliferation, migration and cell morphological changes. These are processes that also play an important role in epithelial-to-mesenchymal transition and cancer cell invasion. In fact, CagA is considered as the only known bacterial oncoprotein. The cellular effects are triggered by a variety of CagA activities including the inhibition of serine-threonine kinase Par1b/MARK2 and the activation of tyrosine phosphatase SHP-2. Additionally, CagA was described to affect the activity of Src family kinases and C-terminal Src kinase (Csk) suggesting that interference with multiple cellular kinase- and phosphatase-associated signalling pathways is a major function of CagA. Here, we describe the effect of CagA on protein kinase C-related kinase 2 (PRK2), which acts downstream of Rho GTPases and is known to affect cytoskeletal rearrangements and cell polarity. CagA interacts with PRK2 and inhibits its kinase activity. Because PRK2 has been linked to cytoskeletal rearrangements and establishment of cell polarity, we suggest that CagA may hijack PRK2 to further manipulate cancer-related signalling pathways.

Results are presented of a search for heavy particles decaying into two photons. The analysis is based on a 19.7 fb(-1) sample of proton-proton collisions at root s = 8 TeV collected with the CMS detector at the CERN LHC. The diphoton mass spectrum from 150 to 850 GeV is used to search for an excess of events over the background. The search is extended to new resonances with natural widths of up to 10% of the mass value. No evidence for new particle production is observed and limits at 95% confidence level on the production cross section times branching fraction to diphotons are determined. These limits are interpreted in terms of two-Higgs-doublet model parameters. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.

The first study of W boson production in pPb collisions is presented, for bosons decaying to a muon or electron, and a neutrino. The measurements are based on a data sample corresponding to an integrated luminosity of 34.6 nb(-1) at a nucleon-nucleon centre-of-mass energy of root(NN)-N-S = 5.02 TeV, collected by the CMS experiment. The W boson differential cross sections, lepton charge asymmetry, and forward-backward asymmetries are measured for leptons of transverse momentum exceeding 25 GeV/c, and as a function of the lepton pseudorapidity in the vertical bar eta(lab)vertical bar < 2.4 range. Deviations from the expectations based on currently available parton distribution functions are observed, showing the need for including W boson data in nuclear parton distribution global fits. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.

microRNAs (miRNAs) act as sequence-specific guides for Argonaute (AGO) proteins, which mediate posttranscriptional silencing of target messenger RNAs. Despite their importance in many biological processes, rules governing AGO-miRNA targeting are only partially understood. Here we report a modified AGO HITS-CLIP strategy termed CLEAR (covalent ligation of endogenous Argonaute-bound RNAs)-CLIP, which enriches miRNAs ligated to their endogenous mRNA targets. CLEAR-CLIP mapped similar to 130,000 endogenous miRNA-target interactions in mouse brain and similar to 40,000 in human hepatoma cells. Motif and structural analysis define expanded pairing rules for over 200 mammalian miRNAs. Most interactions combine seed-based pairing with distinct, miRNA-specific patterns of auxiliary pairing. At some regulatory sites, this specificity confers distinct silencing functions to miRNA family members with shared seed sequences but divergent 3'-ends. This work provides a means for explicit biochemical identification of miRNA sites in vivo, leading to the discovery that miRNA 3'-end pairing is a general determinant of AGO binding specificity.