Unveiling the Noncanonical Activation Mechanism of Cdks: Insights From Recent Structural Studies

The Cyclin-dependent kinases (CDKs) play crucial roles in a range of essential cellular processes. While the classical two-step activation mechanism is generally applicable to cell cycle-related CDKs, both CDK7 and CDK8, involved in transcriptional regulation, adopt distinct mechanisms for kinase activation. In both cases, binding to their respective cyclin partners results in only partial activity, while their full activation requires the presence of an additional subunit. Recent structural studies of these two noncanonical kinases have provided unprecedented insights into their activation mechanisms, enabling us to understand how the third subunit coordinates the T-loop stabilization and enhances kinase activity. In this review, we summarize the structure and function of CDK7 and CDK8 within their respective functional complexes, while also describing their noncanonical activation mechanisms. These insights open new avenues for targeted drug discovery and potential therapeutic interventions in various diseases related to CDK7 and CDK8

Promoting tau secretion and propagation by hyperactive p300/CBP via autophagy-lysosomal pathway in tauopathy.

BackgroundThe trans-neuronal propagation of tau has been implicated in the progression of tau-mediated neurodegeneration. There is critical knowledge gap in understanding how tau is released and transmitted, and how that is dysregulated in diseases. Previously, we reported that lysine acetyltransferase p300/CBP acetylates tau and regulates its degradation and toxicity. However, whether p300/CBP is involved in regulation of tau secretion and propagation is unknown.MethodWe investigated the relationship between p300/CBP activity, the autophagy-lysosomal pathway (ALP) and tau secretion in mouse models of tauopathy and in cultured rodent and human neurons. Through a high-through-put compound screen, we identified a new p300 inhibitor that promotes autophagic flux and reduces tau secretion. Using fibril-induced tau spreading models in vitro and in vivo, we examined how p300/CBP regulates tau propagation.ResultsIncreased p300/CBP activity was associated with aberrant accumulation of ALP markers in a tau transgenic mouse model. p300/CBP hyperactivation blocked autophagic flux and increased tau secretion in neurons. Conversely, inhibiting p300/CBP promoted autophagic flux, reduced tau secretion, and reduced tau propagation in fibril-induced tau spreading models in vitro and in vivo.ConclusionsWe report that p300/CBP, a lysine acetyltransferase aberrantly activated in tauopathies, causes impairment in ALP, leading to excess tau secretion. This effect, together with increased intracellular tau accumulation, contributes to enhanced spreading of tau. Our findings suggest that inhibition of p300/CBP as a novel approach to correct ALP dysfunction and block disease progression in tauopathy

Efficient FPGA implementation of high-throughput mixed radix multipath delay commutator FFT processor for MIMO-OFDM

This article presents and evaluates pipelined architecture designs for an improved high-frequency Fast Fourier Transform (FFT) processor implemented on Field Programmable Gate Arrays (FPGA) for Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM). The architecture presented is a Mixed-Radix Multipath Delay Commutator. The presented parallel architecture utilizes fewer hardware resources compared to Radix-2 architecture, while maintaining simple control and butterfly structures inherent to Radix-2 implementations. The high-frequency design presented allows enhancing system throughput without requiring additional parallel data paths common in other current approaches, the presented design can process two and four independent data streams in parallel and is suitable for scaling to any power of two FFT size N. FPGA implementation of the architecture demonstrated significant resource efficiency and high-throughput in comparison to relevant current approaches within literature. The proposed architecture designs were realized with Xilinx System Generator (XSG) and evaluated on both Virtex-5 and Virtex-7 FPGA devices. Post place and route results demonstrated maximum frequency values over 400 MHz and 470 MHz for Virtex-5 and Virtex-7 FPGA devices respectively

Roles of the Hydrophobic Gate and Exit Channel in Vigna radiata Pyrophosphatase Ion Translocation

Membrane-embedded pyrophosphatase (M-PPase) hydrolyzes pyrophosphate to drive ion (H+ and/or Na+) translocation. We determined crystal structures and functions of Vigna radiata M-PPase (VrH+-PPase), the VrH+-PPase–2Pi complex and mutants at hydrophobic gate (residue L555) and exit channel (residues T228 and E225). Ion pore diameters along the translocation pathway of three VrH+-PPases complexes (Pi-, 2Pi- and imidodiphosphate-bound states) present a unique wave-like profile, with different pore diameters at the hydrophobic gate and exit channel, indicating that the ligands induced pore size alterations. The 2Pi-bound state with the largest pore diameter might mimic the hydrophobic gate open. In mutant structures, ordered waters detected at the hydrophobic gate among VrH+-PPase imply the possibility of solvation, and numerous waters at the exit channel might signify an open channel. A salt-bridge, E225–R562 is at the way out of the exit channel of VrH+-PPase; E225A mutant makes the interaction eliminated and reveals a decreased pumping ability. E225–R562 might act as a latch to regulate proton release. A water wire from the ion gate (R-D-K-E) through the hydrophobic gate and into the exit channel may reflect the path of proton transfer

Use of an asparaginyl endopeptidase for chemo-enzymatic peptide and protein labeling

Asparaginyl endopeptidases (AEPs) are ideal for peptide and protein labeling. However, because of the reaction reversibility, a large excess of labels or backbone modified substrates are needed. In turn, simple and cheap reagents can be used to label N-terminal cysteine, but its availability inherently limits the potential applications. Aiming to address these issues, we have created a chemo-enzymatic labeling system that exploits the substrate promiscuity of AEP with the facile chemical reaction between N-terminal cysteine and 2-formyl phenylboronic acid (FPBA). In this approach, AEP is used to ligate polypeptides with a Asn–Cys–Leu recognition sequence with counterparts possessing an N-terminal Gly–Leu. Instead of being a labeling reagent, the commercially available FPBA serves as a scavenger converting the byproduct Cys–Leu into an inert thiazolidine derivative. This consequently drives the AEP labeling reaction forward to product formation with a lower ratio of label to protein substrate. By carefully screening the reaction conditions for optimal compatibility and minimal hydrolysis, conversion to the ligated product in the model reaction resulted in excellent yields. The versatility of this AEP-ligation/FPBA-coupling system was further demonstrated by site-specifically labeling the N- or C-termini of various proteins

Association between plasma levels of hyaluronic acid and functional outcome in acute stroke patients

BACKGROUND: Activation of hyaluronic acid (HA) and associated enzyme synthesis has been demonstrated in experimental stroke animal models. Our study aimed to investigate the plasma levels of HA in acute stroke patients and the associations between HA levels and functional outcome. METHODS: This was a multicenter case–control study. Acute stroke patients and age- and sex-matched non-stroke controls were recruited. Plasma levels of HA in acute stroke patients were determined at <48 hours and at 48 to 72 hours after stroke onset by standard ELISA. Favorable functional outcome was defined as modified Rankin scale ≤2 at 3 months after stroke. RESULTS: The study included 206 acute stroke patients, including 43 who had intracerebral hemorrhage and 163 who had ischemic stroke, and 159 controls. The plasma levels of HA in the acute stroke patients were significantly higher than those in the controls (219.7 ± 203.4 ng/ml for <48 hours and 343.1 ± 710.3 ng/ml for 48 to 72 hours versus 170.4 ± 127.9 ng/ml in the controls; both P < 0.05). For intracerebral hemorrhage patients, HA ≤500 ng/ml (<48 hours) was an independent favorable outcome predictor (P = 0.016). For ischemic stroke patients, an inverted U-shaped association between plasma HA (48 to 72 hours) and outcome was noted, indicating that ischemic stroke patients with too high or too low plasma HA levels tended to have an unfavorable outcome. CONCLUSION: HA plasma level was elevated in patients with acute stroke, and can predict 3-month functional outcome, particularly for patients with intracerebral hemorrhage

Assessing the Impacts of Experimentally Elevated Temperature on the Biological Composition and Molecular Chaperone Gene Expression of a Reef Coral

Due to the potential for increasing ocean temperatures to detrimentally impact reef-building corals, there is an urgent need to better understand not only the coral thermal stress response, but also natural variation in their sub-cellular composition. To address this issue, while simultaneously developing a molecular platform for studying one of the most common Taiwanese reef corals, Seriatopora hystrix, 1,092 cDNA clones were sequenced and characterized. Subsequently, RNA, DNA and protein were extracted sequentially from colonies exposed to elevated (30°C) temperature for 48 hours. From the RNA phase, a heat shock protein-70 (hsp70)-like gene, deemed hsp/c, was identified in the coral host, and expression of this gene was measured with real-time quantitative PCR (qPCR) in both the host anthozoan and endosymbiotic dinoflagellates (genus Symbiodinium). While mRNA levels were not affected by temperature in either member, hsp/c expression was temporally variable in both and co-varied within biopsies. From the DNA phase, host and Symbiodinium hsp/c genome copy proportions (GCPs) were calculated to track changes in the biological composition of the holobiont during the experiment. While there was no temperature effect on either host or Symbiodinium GCP, both demonstrated significant temporal variation. Finally, total soluble protein was responsive to neither temperature nor exposure time, though the protein/DNA ratio varied significantly over time. Collectively, it appears that time, and not temperature, is a more important driver of the variation in these parameters, highlighting the need to consider natural variation in both gene expression and the molecular make-up of coral holobionts when conducting manipulative studies. This represents the first study to survey multiple macromolecules from both compartments of an endosymbiotic organism with methodologies that reflect their dual-compartmental nature, ideally generating a framework for assessing molecular-level changes within corals and other endosymbioses exposed to changes in their environment

Comparison of the use of prenatal care services and the risk of preterm birth between pregnant women with disabilities and those without disabilities: A nationwide cohort study

ObjectiveThe difficulties faced by pregnant women with disabilities in accessing health care may make them less likely to receive prenatal care. The aims of this study were to compare the number of prenatal services and the risk of preterm birth between pregnant women with and without disabilities.MethodsA total of 2999 pregnant women aged ≥20 years with birth records in 2011–2014 in Taiwan were enrolled. Data were obtained from the Registration File for Physical and Mental Disabilities and the National Health Insurance Research Database. A 1:4 matching between pregnant women with disabilities and those without disabilities was performed. The logistic regression analysis with generalized estimating equations was used to analyze.ResultsThe median of prenatal care services used by pregnant women with disabilities was 9.00 (interquartile range, IQR: 2.00). Pregnant women with disabilities used fewer services than those without disabilities (median, 10.00; IQR: 1.00). The disabled group (8.44%) had a significantly higher proportion of preterm births than did the non-disabled group (5.40%). The disabled group was at a 1.30 times higher risk of preterm births than was the non-disabled group.ConclusionsPregnant women with disabilities used significantly fewer prenatal care services and had a significantly higher risk of preterm birth than pregnant women without disabilities