Phosphoinositide 3 kinase enhancer (PIKE) is a recently identified nuclear GTPase that activates nuclear phosphoinositide 3-kinase (PI3 kinase). We have identified, cloned and characterized a new form of PIKE, designated PIKE-L, which, unlike the nuclear PIKE-S, localizes to both the cytoplasm and the nucleus. We demonstrate physiologic binding of PIKE-L to Homer, an adaptor protein known to link metabotropic glutamate receptors to multiple intracellular targets including the inositol 1,4,5-trisphosphate receptor (IP3R). We show that activation of group I metabotropic glutamate receptors (mGluRIs) enhances formation of an mGluRI-Homer-PIKE-L complex, leading to activation of PI3 kinase activity and prevention of neuronal apoptosis. Our findings indicate that this complex mediates the well-known ability of agonists of mGluRI to prevent neuronal apoptosis.

Background-Essential hypertension has been recognized as a disease resulting from a combination of environmental and genetic factors. Recent studies demonstrated that microRNAs (miRNAs) are involved in cardiac hypertrophy and heart failure. However, little is known about the roles of miRNAs in essential hypertension. Methods and Results-Using microarray-based miRNA expression profiling, we compared the miRNA expressions in plasma samples from 13 hypertensive patients and 5 healthy control subjects. Twenty-seven miRNAs were found to be differentially expressed. The expressions of selected miRNAs (miR-296 -5p, let-7e, and a human cytomegalovirus [HCMV]-encoded miRNA, hcmv-miR-UL112) were validated independently in plasma samples from 24 hypertensive patients and 22 control subjects. The absolute expression levels of hcmv-miR-UL112, miR-296 -5p, and let-7e were further determined in 127 patients and 67 control subjects (fold changes are 2.5, 0.5, and 1.7 respectively; all PϽ0.0001). Additionally, we demonstrated that interferon regulatory factor 1 is a direct target of hcmv-miR-UL112.Increased HCMV seropositivity and quantitative titers were found in the hypertension group compared with the control group (52.7% versus 30.9%, Pϭ0.0005; 1870 versus 54 copies per 1 mL plasma, PϽ0.0001). Seropositivity, log-transformed copies of HCMV, and hcmv-miR-UL112 were independently associated with an increased risk of hypertension (odds ratio, 2.48; 95% confidence interval, 1.48 to 4.15; Pϭ0.0005; odds ratio, 1.97; 95% confidence interval, 1.58 to 2.46; PϽ0.0001; and odds ratio, 2.55; 95% confidence interval, 1.98 to 3.27; PϽ0.0001, respectively). Conclusions-We report for the first time a circulating miRNA profile for hypertensive patients and demonstrate a novel link between HCMV infection and essential hypertension. These findings may reveal important insights into the pathogenesis of essential hypertension. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00420784. Key Words: cytomegalovirus Ⅲ hypertension Ⅲ interferon regulatory factor-1 Ⅲ microRNAs E ssential hypertension is a predisposing risk factor for stroke, myocardial infarction, congestive heart failure, and arterial aneurysm; it is also the leading cause of chronic renal failure. 1 Approximately 90% to 95% of hypertension, affecting Ͼ1 billion adults worldwide, is the essential hypertension subtype. 2 Discernment between essential and secondary hypertension is critical because the former has no precise cause and the latter has a clear cause usually remediable by a Clinical Perspective on p 184 microRNAs (miRNAs) are short, endogenous, noncoding RNAs that regulate gene expression at the posttranscriptional level by binding to the 3Ј untranslated regions (UTRs) of their target mRNAs. 7 Although dysregulation of miRNA expression is a feature of malignancies, 8 -10 research into miRNAs in biological processes reveals their regulation of immune cell development, 11 involvement in inflammatory response, 12 and critical participation...

One aim for an HIV vaccine is to elicit neutralizing antibodies (Nab) that can limit replication of genetically diverse viruses and prevent establishment of a new infection. Thus, identifying the strengths and weaknesses of Nab during the early stages of natural infection could prove useful in achieving this goal. Here we demonstrate that viral escape readily occurred despite the development of high titer autologous Nab in two subjects with acute/early subtype C infection. To provide a detailed portrayal of the escape pathways, Nab resistant variants identified at multiple time points were used to create a series of envelope (Env) glycoprotein chimeras and mutants within the background of a corresponding newly transmitted Env. In one subject, Nab escape was driven predominantly by changes in the region of gp120 that extends from the beginning of the V3 domain to the end of the V5 domain (V3V5). However, Nab escape pathways in this subject oscillated and at times required cooperation between V1V2 and the gp41 ectodomain. In the second subject, escape was driven by changes in V1V2. This V1V2-dependent escape pathway was retained over time, and its utility was reflected in the virus's ability to escape from two distinct monoclonal antibodies (Mabs) derived from this same patient via introduction of a single potential N-linked glycosylation site in V2. Spatial representation of the sequence changes in gp120 suggested that selective pressure acted upon the same regions of Env in these two subjects, even though the Env domains that drove escape were different. Together the findings argue that a single mutational pathway is not sufficient to confer escape in early subtype C HIV-1 infection, and support a model in which multiple strategies, including potential glycan shifts, direct alteration of an epitope sequence, and cooperative Env domain conformational masking, are used to evade neutralization.

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Akt/PKB is a crucial regulator of diverse cellular processes and contributes to cancer progression. Activation of Akt is essentially dependent on phosphatidylinositol (PI) 3-kinase signaling. Here, we describe a novel mediator of Akt that is independent of PI 3-kinase. This mediator, PIKE-A, is a PIKE isoform and contains GTPase, pleckstrin homology, ArfGAP, and ankyrin repeats domains. PIKE-A directly binds to activated Akt but not PI 3-kinase in a guanine nucleotide-dependent way and stimulates the kinase activity of Akt. Overexpression of PIKE-A enhances Akt activity and promotes cancer cell invasion, whereas dominant-negative PIKE-A and PIKE-A knockdown markedly inhibit these processes. Our results demonstrate that PIKE-A is a physiologic regulator of Akt and an oncogenic effector of cell invasion.

N 6-Methyladenosine (m6A) is the most prevalent RNA modification on mRNAs and lncRNAs. It plays a pivotal role during various biological processes and disease pathogenesis. We present here a comprehensive knowledgebase, m6A-Atlas, for unraveling the m6A epitranscriptome. Compared to existing databases, m6A-Atlas features a high-confidence collection of 442 162 reliable m6A sites identified from seven base-resolution technologies and the quantitative (rather than binary) epitranscriptome profiles estimated from 1363 high-throughput sequencing samples. It also offers novel features, such as; the conservation of m6A sites among seven vertebrate species (including human, mouse and chimp), the m6A epitranscriptomes of 10 virus species (including HIV, KSHV and DENV), the putative biological functions of individual m6A sites predicted from epitranscriptome data, and the potential pathogenesis of m6A sites inferred from disease-associated genetic mutations that can directly destroy m6A directing sequence motifs. A user-friendly graphical user interface was constructed to support the query, visualization and sharing of the m6A epitranscriptomes annotated with sites specifying their interaction with post-transcriptional machinery (RBP-binding, microRNA interaction and splicing sites) and interactively display the landscape of multiple RNA modifications. These resources provide fresh opportunities for unraveling the m6A epitranscriptomes. m6A-Atlas is freely accessible at: www.xjtlu.edu.cn/biologicalsciences/atlas.

N 6 -methyladenosine (m 6 A) is the most prevalent post-transcriptional modification in eukaryotes, and plays a pivotal role in various biological processes, such as splicing, RNA degradation and RNA–protein interaction. We report here a prediction framework WHISTLE for transcriptome-wide m 6 A RNA-methylation site prediction. When tested on six independent datasets, our approach, which integrated 35 additional genomic features besides the conventional sequence features, achieved a major improvement in the accuracy of m 6 A site prediction (average AUC: 0.948 and 0.880 under the full transcript or mature messenger RNA models, respectively) compared to the state-of-the-art computational approaches MethyRNA (AUC: 0.790 and 0.732) and SRAMP (AUC: 0.761 and 0.706). It also out-performed the existing epitranscriptome databases MeT-DB (AUC: 0.798 and 0.744) and RMBase (AUC: 0.786 and 0.736), which were built upon hundreds of epitranscriptome high-throughput sequencing samples. To probe the putative biological processes impacted by changes in an individual m 6 A site, a network-based approach was implemented according to the ‘guilt-by-association’ principle by integrating RNA methylation profiles, gene expression profiles and protein–protein interaction data. Finally, the WHISTLE web server was built to facilitate the query of our high-accuracy map of the human m 6 A epitranscriptome, and the server is freely available at: www.xjtlu.edu.cn/biologicalsciences/whistle and http://whistle-epitranscriptome.com .

Autologous neutralizing antibodies (NAb) against human immunodeficiency virus type 1 generate viral escape variants; however, the mechanisms of escape are not clearly defined. In a previous study, we determined the susceptibilities of 48 donor and 25 recipient envelope (Env) glycoproteins from five subtype C heterosexual transmission pairs to NAb in donor plasma by using a virus pseudotyping assay, thereby providing an ideal setting to probe the determinants of susceptibility to neutralization. In the present study, acquisition of length in the Env gp120 hypervariable domains was shown to correlate with resistance to NAb in donor plasma (P ‫؍‬ 0.01; Kendall's tau test) but not in heterologous plasma. Sequence divergence in the gp120 V1-to-V4 region also correlated with resistance to donor (P ‫؍‬ 0.0002) and heterologous (P ‫؍‬ 0.001) NAb. A mutual information analysis suggested possible associations of nine amino acid positions in V1 to V4 with NAb resistance to the donor's antibodies, and five of these were located within an 18-residue amphipathic helix (␣2) located on the gp120 outer domain. High nonsynonymous-to-synonymous substitution (dN/dS) ratios, indicative of positive selection, were also found at these five positions in subtype C sequences in the database. Nevertheless, exchange of the entire ␣2 helix between resistant donor Envs and sensitive recipient Envs did not alter the NAb phenotype. The combined mutual information and dN/dS analyses suggest that unique mutational patterns in ␣2 and insertions in the V1-to-V4 region are associated with NAb resistance during subtype C infection but that the selected positions within the ␣2 helix must be linked to still other changes in Env to confer antibody escape. These findings suggest that subtype C viruses utilize mutations in the ␣2 helix for efficient viral replication and immune avoidance.