Casein kinase CK2 structure and activities in plants

A comprehensive review on the dynamics of protein kinase CK2 in cancer development and optimizing therapeutic strategies

Protein kinase 2 (CK2) is an enzyme ubiquitously present and exhibits extensive kinase activity. It has been strongly linked to tumor progression through the abnormal phosphorylation of key proteins. Research has consistently demonstrated that CK2 is deregulated in various cancer types, with enhanced protein expression and nuclear distribution in tumor cells. CK2 plays a crucial role in a complex network that promotes cell infiltration, migration, proliferation, apoptosis, and cancer progression through multiple pathways, including PI3K/AKT, JAK2/STAT3, ATF4/CDKN1, and HSP90/Cdc37. In addition to its role in cancer growth, there is mounting evidence that CK2 may also affect the immunological dynamics of cancer by altering immune cell functions within the tumor microenvironment, thus facilitating tumor immune evasion. Recent research has increasingly focused on CK2, recognizing it as a therapeutic objective for oncological interventions. This review will critically examine the structure and signaling pathways of CK2, highlighting the significance of further research aimed at enhancing our understanding of the CK2 machinery. Finally, we conclude by refining therapeutic options, notably transitioning from non-pharmacological techniques to strategic CK2 inhibitor use. This development shortens the path to the desired outcome, establishing a pioneering standard in cancer therapy.

The Janus face of mitophagy in myocardial ischemia/reperfusion injury and recovery

In myocardial ischemia/reperfusion injury (MIRI), moderate mitophagy is a protective or adaptive mechanism because of clearing defective mitochondria accumulates during MIRI. However, excessive mitophagy lead to an increase in defective mitochondria and ultimately exacerbate MIRI by causing overproduction or uncontrolled production of mitochondria. Phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1), Parkin, FUN14 domain containing 1 (FUNDC1) and B-cell leukemia/lymphoma 2 (BCL-2)/adenovirus E1B19KD interaction protein 3 (BNIP3) are the main mechanistic regulators of mitophagy in MIRI. Pink1 and Parkin are mitochondrial surface proteins involved in the ubiquitin-dependent pathway, while BNIP3 and FUNDC1 are mitochondrial receptor proteins involved in the non-ubiquitin-dependent pathway, which play a crucial role in maintaining mitochondrial homeostasis and mitochondrial quality. These proteins can induce moderate mitophagy or inhibit excessive mitophagy to protect against MIRI but may also trigger excessive mitophagy or insufficient mitophagy, thereby worsening the condition. Understanding the actions of these mitophagy mechanistic proteins may provide valuable insights into the pathological mechanisms underlying MIRI development. Based on the above background, this article reviews the mechanism of mitophagy involved in MIRI through Pink1/Parkin pathway and the receptor mediated pathway led by FUNDC1 and BNIP3, as well as the related drug treatment, aim to provide effective strategies for the prevention and treatment of MIRI.

The prefoldin-like protein AtURI exhibits characteristics of intrinsically disordered proteins

The prefoldin-like protein UNCONVENTIONAL PREFOLDIN RPB5 INTERACTOR (URI) participates in diverse cellular functions, including protein homeostasis, transcription, translation, and signal transduction. Thus, URI is a highly versatile protein, although the molecular basis of this versatility remains unknown. In this work, we show that Arabidopsis thaliana (Arabidopsis) URI (AtURI) possesses a large intrinsically disordered region (IDR) spanning most of the C-terminal part of the protein, a feature conserved in yeast and human orthologs. Our findings reveal two key characteristics of disordered proteins in AtURI: promiscuity in interacting with partners and protein instability. We propose that these two features contribute to providing AtURI with functional versatility.

Identification of Salt-Sensitive and Salt-Tolerant Genes through Weighted Gene Co-Expression Networks across Multiple Datasets: A Centralization and Differential Correlation Analysis

Salt stress is a significant challenge that severely hampers rice growth, resulting in decreased yield and productivity. Over the years, researchers have identified biomarkers associated with salt stress to enhance rice tolerance. However, the understanding of the mechanism underlying salt tolerance in rice remains incomplete due to the involvement of multiple genes. Given the vast amount of genomics and transcriptomics data available today, it is crucial to integrate diverse datasets to identify key genes that play essential roles during salt stress in rice. In this study, we propose an integration of multiple datasets to identify potential key transcription factors. This involves utilizing network analysis based on weighted co-expression networks, focusing on gene-centric measurement and differential co-expression relationships among genes. Consequently, our analysis reveals 86 genes located in markers from previous meta-QTL analysis. Moreover, six transcription factors, namely LOC_Os03g45410 (OsTBP2), LOC_Os07g42400 (OsGATA23), LOC_Os01g13030 (OsIAA3), LOC_Os05g34050 (OsbZIP39), LOC_Os09g29930 (OsBIM1), and LOC_Os10g10990 (transcription initiation factor IIF), exhibited significantly altered co-expression relationships between salt-sensitive and salt-tolerant rice networks. These identified genes hold potential as crucial references for further investigation into the functions of salt stress response in rice plants and could be utilized in the development of salt-resistant rice cultivars. Overall, our findings shed light on the complex genetic regulation underlying salt tolerance in rice and contribute to the broader understanding of rice's response to salt stress.

Protein pyrophosphorylation by inositol phosphates: a novel post-translational modification in plants?

Inositol pyrophosphates (PP-InsPs) are energy-rich molecules harboring one or more diphosphate moieties. PP-InsPs are found in all eukaryotes evaluated and their functional versatility is reflected in the various cellular events in which they take part. These include, among others, insulin signaling and intracellular trafficking in mammals, as well as innate immunity and hormone and phosphate signaling in plants. The molecular mechanisms by which PP-InsPs exert such functions are proposed to rely on the allosteric regulation via direct binding to proteins, by competing with other ligands, or by protein pyrophosphorylation. The latter is the focus of this review, where we outline a historical perspective surrounding the first findings, almost 20 years ago, that certain proteins can be phosphorylated by PP-InsPs in vitro. Strikingly, in vitro phosphorylation occurs by an apparent enzyme-independent but Mg2+-dependent transfer of the β-phosphoryl group of an inositol pyrophosphate to an already phosphorylated serine residue at Glu/Asp-rich protein regions. Ribosome biogenesis, vesicle trafficking and transcription are among the cellular events suggested to be modulated by protein pyrophosphorylation in yeast and mammals. Here we discuss the latest efforts in identifying targets of protein pyrophosphorylation, pointing out the methodological challenges that have hindered the full understanding of this unique post-translational modification, and focusing on the latest advances in mass spectrometry that finally provided convincing evidence that PP-InsP-mediated pyrophosphorylation also occurs in vivo. We also speculate about the relevance of this post-translational modification in plants in a discussion centered around the protein kinase CK2, whose activity is critical for pyrophosphorylation of animal and yeast proteins. This enzyme is widely present in plant species and several of its functions overlap with those of PP-InsPs. Until now, there is virtually no data on pyrophosphorylation of plant proteins, which is an exciting field that remains to be explored.