Significance: Structural and functional studies on protein kinase CK2α, which is a ubiquitous kinase that can phosphorylate hundreds of cellular proteins, revealed that CK2α activity is inhibited by Nopp140 and reactivated by IP ₆ by competitive binding at the substrate recognition site of CK2α. IP ₆ binds to the lysine-rich cluster of CK2α, and phospho-Ser574 on Nopp140 significantly enhances its interaction with CK2α.

Apocynin (Apo), an NADPH oxidase (NOX) inhibitor, has been widely used to treat various inflammatory diseases. However, the therapeutic effects of Apo on benign prostatic hyperplasia (BPH), a multifactorial disease associated with chronic inflammation and hormone imbalance, remain unknown. The link between androgen signaling, reactive oxygen species (ROS), and prostate cell proliferation may contribute to the pathogenesis of BPH; therefore, the aim of this study was to identify the specific signaling pathway involved and to demonstrate whether the anti-oxidant Apo plays a role in the prevention and treatment of BPH. Ingenuity pathway analysis and si-RNA transfection were conducted to demonstrate the androgen receptor (AR) and NOX4 linkage in BPH. Pathological markers of BPH were measured by H&E staining, immunoblotting, ELISA, qRT-PCR, and immunofluorescence to examine the effect of Apo. Rats stimulated with testosterone and BPH-1 cells were used as BPH models. AR and NOX4 network-mediated oxidative stress was upregulated in the BPH model. Next, we examined the effects of Apo on oxidative stress and chronic prostatic inflammation in BPH mouse models. In a testosterone-induced BPH rat model, Apo alleviated pathological prostate enlargement and suppressed androgen/AR signaling. Apo suppressed the upregulation of proinflammatory markers and promoted the expression of anti-oxidant factors. Furthermore, Apo regulated the TGF-β/Glut9/activin pathway and macrophage programming. In BPH-1 cells, Apo suppressed AR-mediated proliferation and upregulation of TGFB and NOX4 expression by alleviating oxidative stress. Apo activated anti-oxidant and anti-inflammatory systems and regulated macrophage polarization in BPH-1 cells. AR knockdown partially abolished the beneficial effects of Apo in prostate cells, indicating AR-dependent effects of Apo. In contrast with existing BPH therapies, Apo may provide a new application for prostatic disease treatment, especially for BPH, by targeting the AR/TGF-β/NOX4 signaling pathway.

Targeted delivery of therapeutic agents is of particular interest in the field of cancer treatment. However, there is an urgent need for developing clinically promising targeting approaches that can be readily administered in a green manner.

Significance: Germ cells possess the inherent ability to inactivate cell abscission through TEX14 (testis-expressed gene 14), and they may provide information on inactivation of the abscission in abnormal cells, including cancer cells. Structural and functional studies of how TEX14 inactivates germ cell abscission reveal that the AxGPPx ₃ YxPP motif of TEX14 competitively binds to CEP55-EABR [endosomal sorting complex required for transport (ESCRT) and ALIX-binding region] to prevent the recruitment of ALIX, which is a component of the ESCRT machinery and which contains the AxGPPx ₃ Y motif. Multiexperiment analyses of CEP55-EABR–TEX14 interactions showed how the TEX14 peptide binds dominantly to CEP55-EABR in the presence of ALIX and safeguards the intercellular bridges of germ cells.

Intrinsically disordered proteins (IDPs) represent approximately 30% of the human genome and play key roles in cell proliferation and cellular signaling by modulating the function of target proteins via protein–protein interactions. In addition, IDPs are involved in various human disorders, such as cancer, neurodegenerative diseases, and amyloidosis. To understand the underlying molecular mechanism of IDPs, it is important to study their structural features during their interactions with target proteins. However, conventional biochemical and biophysical methods for analyzing proteins, such as X-ray crystallography, have difficulty in characterizing the features of IDPs because they lack an ordered three-dimensional structure. Here, we present biochemical and biophysical studies on nucleolar phosphoprotein 140 (Nopp140), which mostly consists of disordered regions, during its interaction with casein kinase 2 (CK2), which plays a central role in cell growth. Surface plasmon resonance and electron paramagnetic resonance studies were performed to characterize the interaction between Nopp140 and CK2. A single-molecule fluorescence resonance energy transfer study revealed conformational change in Nopp140 during its interaction with CK2. These studies on Nopp140 can provide a good model system for understanding the molecular function of IDPs.