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Plant Signaling & Behavior Dec 2023Hypoxia triggers reactive oxygen species (ROS)-induced elevation in cytoplasmic calcium (Ca) in the plant cells. Calcium-dependent protein kinase 12 (CPK12) acts as a...
Hypoxia triggers reactive oxygen species (ROS)-induced elevation in cytoplasmic calcium (Ca) in the plant cells. Calcium-dependent protein kinase 12 (CPK12) acts as a sensor to recognize the Ca signature and is activated by autophosphorylation. Then, the CPK12 moves into the nucleus with the help of phosphatidic acid (PA) and phosphorylates ERF-VII family proteins that activate hypoxia signaling and response. The study provides a novel mechanism of hypoxia signaling in plants. Moreover, the mechanism of hypoxia-specific Ca signature generation remains elusive.
Topics: Protein Kinases; Hypoxia; Cell Hypoxia; Phosphorylation; Calcium; Reactive Oxygen Species
PubMed: 37875477
DOI: 10.1080/15592324.2023.2273593 -
Science Advances Jan 2024The ubiquitin kinase PINK1 accumulates on damaged mitochondria to trigger mitophagy, and PINK1 loss-of-function mutations cause early onset Parkinson's disease....
The ubiquitin kinase PINK1 accumulates on damaged mitochondria to trigger mitophagy, and PINK1 loss-of-function mutations cause early onset Parkinson's disease. Nucleotide analogs such as kinetin triphosphate (KTP) were reported to enhance PINK1 activity and may represent a therapeutic strategy for the treatment of Parkinson's disease. Here, we investigate the interaction of PINK1 with nucleotides, including KTP. We establish a cryo-EM platform exploiting the dodecamer assembly of () PINK1 and determine PINK1 structures bound to AMP-PNP and ADP, revealing conformational changes in the kinase N-lobe that help establish PINK1's ubiquitin binding site. Notably, we find that KTP is unable to bind PINK1 or human () PINK1 due to a steric clash with the kinase "gatekeeper" methionine residue, and mutation to Ala or Gly is required for PINK1 to bind and use KTP as a phosphate donor in ubiquitin phosphorylation and mitophagy. PINK1 M318G can be used to conditionally uncouple PINK1 stabilization and activity on mitochondria.
Topics: Humans; Protein Kinases; Parkinson Disease; Kinetin; Nucleotides; Ubiquitin
PubMed: 38241364
DOI: 10.1126/sciadv.adj7408 -
Cell Reports Jul 2023Bacterial cell-wall hydrolases must be tightly regulated during bacterial cell division to prevent aberrant cell lysis and to allow final separation of viable daughter...
Bacterial cell-wall hydrolases must be tightly regulated during bacterial cell division to prevent aberrant cell lysis and to allow final separation of viable daughter cells. In a multidisciplinary work, we disclose the molecular dialogue between the cell-wall hydrolase LytB, wall teichoic acids, and the eukaryotic-like protein kinase StkP in Streptococcus pneumoniae. After characterizing the peptidoglycan recognition mode by the catalytic domain of LytB, we further demonstrate that LytB possesses a modular organization allowing the specific binding to wall teichoic acids and to the protein kinase StkP. Structural and cellular studies notably reveal that the temporal and spatial localization of LytB is governed by the interaction between specific modules of LytB and the final PASTA domain of StkP. Our data collectively provide a comprehensive understanding of how LytB performs final separation of daughter cells and highlights the regulatory role of eukaryotic-like kinases on lytic machineries in the last step of cell division in streptococci.
Topics: Streptococcus pneumoniae; Protein Serine-Threonine Kinases; Teichoic Acids; Bacterial Proteins; Cell Division; Protein Kinases; Hydrolases; Cell Wall
PubMed: 37418323
DOI: 10.1016/j.celrep.2023.112756 -
Molecules (Basel, Switzerland) Aug 2023In drug discovery, protein kinase inhibitors (PKIs) are intensely investigated as drug candidates in different therapeutic areas. While ATP site-directed, non-covalent...
In drug discovery, protein kinase inhibitors (PKIs) are intensely investigated as drug candidates in different therapeutic areas. While ATP site-directed, non-covalent PKIs have long been a focal point in protein kinase (PK) drug discovery, in recent years, there has been increasing interest in allosteric PKIs (APKIs), which are expected to have high kinase selectivity. In addition, as compounds acting by covalent mechanisms experience a renaissance in drug discovery, there is also increasing interest in covalent PKIs (CPKIs). There are various reasons for this increasing interest such as the anticipated high potency, prolonged residence times compared to non-competitive PKIs, and other favorable pharmacokinetic properties. Due to the popularity of PKIs for therapeutic intervention, large numbers of PKIs and large volumes of activity data have accumulated in the public domain, providing a basis for large-scale computational analysis. We have systematically searched for CPKIs containing different reactive groups (warheads) and investigated their potency and promiscuity (multi-PK activity) on the basis of carefully curated activity data. For seven different warheads, sufficiently large numbers of CPKIs were available for detailed follow-up analysis. For only three warheads, the median potency of corresponding CPKIs was significantly higher than of non-covalent PKIs. However, for CKPIs with five of seven warheads, there was a significant increase in the median potency of at least 100-fold compared to PKI analogues without warheads. However, in the analysis of multi-PK activity, there was no general increase in the promiscuity of CPKIs compared to non-covalent PKIs. In addition, we have identified 29 new APKIs in X-ray structures of PK-PKI complexes. Among structurally characterized APKIs, 13 covalent APKIs in complexes with five PKs are currently available, enabling structure-based investigation of PK inhibition by covalent-allosteric mechanisms.
Topics: Protein Kinase Inhibitors; Protein Kinases; Phosphorylation; Drug Discovery
PubMed: 37570774
DOI: 10.3390/molecules28155805 -
FASEB Journal : Official Publication of... Sep 20233-Phosphoinositide-dependent protein kinase-1 (Pdk1) as a serine/threonine protein kinase plays a critical role in multiple signaling pathways. Analysis of the gene...
3-Phosphoinositide-dependent protein kinase-1 (Pdk1) as a serine/threonine protein kinase plays a critical role in multiple signaling pathways. Analysis of the gene expression omnibus database showed that Pdk1 was significantly downregulated in patients with heart diseases. Gene set enrichment analysis of the proteomics dataset identified apoptotic- and metabolism-related signaling pathways directly targeted by Pdk1. Previously, our research indicated that Pdk1 deletion-induced metabolic changes might be involved in the pathogenesis of heart failure; however, the underlying mechanism remains elusive. Here, we demonstrated that deficiency of Pdk1 resulted in apoptosis, oxidative damage, and disturbed metabolism, both in vivo and in vitro. Furthermore, profiling of metabonomics by H-NMR demonstrated that taurine was the major differential metabolite in the heart of Pdk1-knockout mice. Taurine treatment significantly reduced the reactive oxygen species production and apoptosis, improved cardiac function, and prolonged the survival time in Pdk1 deficient mice. Proteomic screening identified solute carrier family 6 member 6 (Slc6a6) as the downstream that altered taurine levels in Pdk1-expression cells. Consistently, cellular apoptosis and oxidative damage were rescued by Slc6a6 in abnormal Pdk1 expression cells. These findings collectively suggest that Pdk1 deficiency induces heart failure via disturbances in taurine homeostasis, triggered by Slc6a6.
Topics: Animals; Mice; 3-Phosphoinositide-Dependent Protein Kinases; Heart Failure; Homeostasis; Mice, Knockout; Protein Kinases; Proteomics; Taurine; Pyruvate Dehydrogenase Acetyl-Transferring Kinase
PubMed: 37561545
DOI: 10.1096/fj.202300272R -
Autophagy Mar 2024As a key regulator of development, organ size, tissue homeostasis and cancer, the Hippo pathway is tightly regulated by various growth-related signaling events. Among...
As a key regulator of development, organ size, tissue homeostasis and cancer, the Hippo pathway is tightly regulated by various growth-related signaling events. Among them, energy stress activates the Hippo pathway to inhibit its downstream effector YAP1. Our recent work reported a YAP1-independent role of the Hippo pathway in promoting macroautophagy/autophagy and cell survival in response to energy stress, a process mediated by Hippo kinase MAP4K2. MAP4K2 interacts with and phosphorylates MAP1LC3A/LC3A at S87, which in turn drives autophagosome-lysosome fusion via the RAB3GAP-RAB18 axis. Energy stress activates MAP4K2 by reducing its association with the Hippo phosphatase complex STRIPAK component STRN4. Moreover, MAP4K2 is highly expressed in head and neck cancer, while MAP4K2 and its mediated autophagy are required for head and neck cancer development. Taken together, our study not only reveals a noncanonical role of the Hippo pathway in energy stress response, but also suggests Hippo kinase MAP4K2 as a potential therapeutic target for head and neck cancer treatment. AMPK: 5'-AMP-activated protein kinase; Atg8: autophagy related 8; LATS1: large tumor suppressor 1; LIR: microtubule-associated protein 1 light chain 3-interacting region; MAP1LC3A/LC3A: microtubule-associated protein 1 light chain 3 alpha; MAP4K2: mitogen-activated protein kinase kinase kinase kinase 2; PPP2/PP2A: protein phosphatase 2; RAB3GAP: RAB3 GTPase activating protein; RAB18: RAB18, member RAS oncogene family; SLMAP: sarcolemma associated protein; STK3/MST2: serine/threonine kinase 3; STK4/MST1: serine/threonine kinase 4; STRIPAK: striatin-interacting phosphatase and kinase; STRN4: striatin, calmodulin binding protein 4; SQSTM1/p62: sequestosome 1; TEAD: TEA domain family member; ULK1: unc-51 like kinase 1; WWTR1/TAZ: WW domain containing transcription regulator 1; YAP1: yes-associated protein 1.
Topics: Humans; Hippo Signaling Pathway; Autophagy; Protein Serine-Threonine Kinases; Intracellular Signaling Peptides and Proteins; Adaptor Proteins, Signal Transducing; AMP-Activated Protein Kinases; Transcription Factors; Microtubule-Associated Proteins; Phosphoric Monoester Hydrolases; Head and Neck Neoplasms; Serine; Serine-Threonine Kinase 3; Calmodulin-Binding Proteins
PubMed: 37937799
DOI: 10.1080/15548627.2023.2280876 -
EMBO Reports Aug 2023The protein kinase PINK1 and ubiquitin ligase Parkin promote removal of damaged mitochondria via a feed-forward mechanism involving ubiquitin (Ub) phosphorylation (pUb),...
The protein kinase PINK1 and ubiquitin ligase Parkin promote removal of damaged mitochondria via a feed-forward mechanism involving ubiquitin (Ub) phosphorylation (pUb), Parkin activation, and ubiquitylation of mitochondrial outer membrane proteins to support the recruitment of mitophagy receptors. The ubiquitin ligase substrate receptor FBXO7/PARK15 is mutated in an early-onset parkinsonian-pyramidal syndrome. Previous studies have proposed a role for FBXO7 in promoting Parkin-dependent mitophagy. Here, we systematically examine the involvement of FBXO7 in depolarization and UPR-dependent mitophagy in the well-established HeLa and induced-neurons cell systems. We find that FBXO7 cells have no demonstrable defect in: (i) kinetics of pUb accumulation, (ii) pUb puncta on mitochondria by super-resolution imaging, (iii) recruitment of Parkin and autophagy machinery to damaged mitochondria, (iv) mitophagic flux, and (v) mitochondrial clearance as quantified by global proteomics. Moreover, global proteomics of neurogenesis in the absence of FBXO7 reveals no obvious alterations in mitochondria or other organelles. These results argue against a general role for FBXO7 in Parkin-dependent mitophagy and point to the need for additional studies to define how FBXO7 mutations promote parkinsonian-pyramidal syndrome.
Topics: Humans; HeLa Cells; Mitophagy; Ubiquitin-Protein Ligases; Protein Kinases; Ubiquitin; F-Box Proteins
PubMed: 37334901
DOI: 10.15252/embr.202256399 -
Molecular Therapy : the Journal of the... Jan 2024Fibrolamellar hepatocellular carcinoma (FLC) is a rare liver cancer caused by a dominant recurrent fusion of the heat shock protein (DNAJB1) and the catalytic subunit of...
Fibrolamellar hepatocellular carcinoma (FLC) is a rare liver cancer caused by a dominant recurrent fusion of the heat shock protein (DNAJB1) and the catalytic subunit of protein kinase A (PRKACA). Current therapies such as chemotherapy and radiation have limited efficacy, and new treatment options are needed urgently. We have previously shown that FLC tumors are dependent on the fusion kinase DNAJB1::PRKACA, making the oncokinase an ideal drug target. mRNA degrading modalities such as antisense oligonucleotides or small interfering RNAs (siRNAs) provide an opportunity to specifically target the fusion junction. Here, we identify a potent and specific siRNA that inhibits DNAJB1::PRKACA expression. We found expression of the asialoglycoprotein receptor in FLC to be maintained at sufficient levels to effectively deliver siRNA conjugated to the GalNAc ligand. We observe productive uptake and siRNA activity in FLC patient-derived xenografts (PDX) models in vitro and in vivo. Knockdown of DNAJB1::PRKACA results in durable growth inhibition of FLC PDX in vivo with no detectable toxicities. Our results suggest that this approach could be a treatment option for FLC patients.
Topics: Humans; Carcinoma, Hepatocellular; Liver Neoplasms; RNA, Small Interfering; Cyclic AMP-Dependent Protein Kinases; RNA, Double-Stranded; HSP40 Heat-Shock Proteins; Cyclic AMP-Dependent Protein Kinase Catalytic Subunits
PubMed: 37980543
DOI: 10.1016/j.ymthe.2023.11.012 -
European Journal of Medicinal Chemistry Feb 2024Polo-like kinase 4 (PLK4), a highly conserved serine/threonine kinase, masterfully regulates centriole duplication in a spatiotemporal manner to ensure the fidelity of... (Review)
Review
Polo-like kinase 4 (PLK4), a highly conserved serine/threonine kinase, masterfully regulates centriole duplication in a spatiotemporal manner to ensure the fidelity of centrosome duplication and proper mitosis. Abnormal expression of PLK4 contributes to genomic instability and associates with a poor prognosis in cancer. Inhibition of PLK4 is demonstrated to exhibit significant efficacy against various types of human cancers, further highlighting its potential as a promising therapeutic target for cancer treatment. As such, numerous small-molecule inhibitors with distinct chemical scaffolds targeting PLK4 have been extensively investigated for the treatment of different human cancers, with several undergoing clinical evaluation (e.g., CFI-400945). Here, we review the structure, distribution, and biological functions of PLK4, encapsulate its intricate regulatory mechanisms of expression, and highlighting its multifaceted roles in cancer development and metastasis. Moreover, the recent advancements of PLK4 inhibitors in patent or literature are summarized, and their therapeutic potential as monotherapies or combination therapies with other anticancer agents are also discussed.
Topics: Humans; Cell Cycle; Mitosis; Neoplasms; Polo-like Kinases; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases
PubMed: 38199166
DOI: 10.1016/j.ejmech.2023.116115 -
Nature Communications Jan 2024Aspergillus fumigatus is a saprophytic fungus that can cause a variety of human diseases known as aspergillosis. Mycotoxin gliotoxin (GT) production is important for its...
Aspergillus fumigatus is a saprophytic fungus that can cause a variety of human diseases known as aspergillosis. Mycotoxin gliotoxin (GT) production is important for its virulence and must be tightly regulated to avoid excess production and toxicity to the fungus. GT self-protection by GliT oxidoreductase and GtmA methyltransferase activities is related to the subcellular localization of these enzymes and how GT can be sequestered from the cytoplasm to avoid increased cell damage. Here, we show that GliT:GFP and GtmA:GFP are localized in the cytoplasm and in vacuoles during GT production. The Mitogen-Activated Protein kinase MpkA is essential for GT production and self-protection, interacts physically with GliT and GtmA and it is necessary for their regulation and subsequent presence in the vacuoles. The sensor histidine kinase SlnA is important for modulation of MpkA phosphorylation. Our work emphasizes the importance of MpkA and compartmentalization of cellular events for GT production and self-defense.
Topics: Humans; Aspergillus fumigatus; Gliotoxin; Fungal Proteins; Mitogen-Activated Protein Kinases; Aspergillosis
PubMed: 38167253
DOI: 10.1038/s41467-023-44329-1