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Essays in Biochemistry Sep 2022Plant immunity is crucial to plant health but comes at an expense. For optimal plant growth, tight immune regulation is required to prevent unnecessary rechannelling of... (Review)
Review
Plant immunity is crucial to plant health but comes at an expense. For optimal plant growth, tight immune regulation is required to prevent unnecessary rechannelling of valuable resources. Pattern- and effector-triggered immunity (PTI/ETI) represent the two tiers of immunity initiated after sensing microbial patterns at the cell surface or pathogen effectors secreted into plant cells, respectively. Recent evidence of PTI-ETI cross-potentiation suggests a close interplay of signalling pathways and defense responses downstream of perception that is still poorly understood. This review will focus on controls on plant immunity through phosphorylation, a universal and key cellular regulatory mechanism. Rather than a complete overview, we highlight "what's new in protein kinase/phosphatase signalling" in the immunity field. In addition to phosphoregulation of components in the pattern recognition receptor (PRR) complex, we will cover the actions of the major immunity-relevant intracellular protein kinases/phosphatases in the 'signal relay', namely calcium-regulated kinases (e.g. calcium-dependent protein kinases, CDPKs), mitogen-activated protein kinases (MAPKs), and various protein phosphatases. We discuss how these factors define a phosphocode that generates cellular decision-making 'logic gates', which contribute to signalling fidelity, amplitude, and duration. To underscore the importance of phosphorylation, we summarize strategies employed by pathogens to subvert plant immune phosphopathways. In view of recent game-changing discoveries of ETI-derived resistosomes organizing into calcium-permeable pores, we speculate on a possible calcium-regulated phosphocode as the mechanistic control of the PTI-ETI continuum.
Topics: Calcium; Mitogen-Activated Protein Kinases; Phosphoprotein Phosphatases; Plant Immunity; Protein Kinases; Receptors, Pattern Recognition
PubMed: 35723080
DOI: 10.1042/EBC20210088 -
EMBO Reports Feb 2022Mitogen-activated protein kinase (MAPK) cascades are important signaling modules regulating diverse biological processes. During the past 20 years, much progress has... (Review)
Review
Mitogen-activated protein kinase (MAPK) cascades are important signaling modules regulating diverse biological processes. During the past 20 years, much progress has been made on the functions of MAPK cascades in plants. This review summarizes the roles of MAPKs, known MAPK substrates, and our current understanding of MAPK cascades in plant development and innate immunity. In addition, recent findings on the molecular links connecting surface receptors to MAPK cascades and the mechanisms underlying MAPK signaling specificity are also discussed.
Topics: Biological Phenomena; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Plant Development; Signal Transduction
PubMed: 35041234
DOI: 10.15252/embr.202153817 -
Journal of Computer-aided Molecular... Mar 2020Small molecules binding at any of the multiple regulatory sites on the molecular surface of a protein kinase may stabilize or disrupt the corresponding interaction,...
Small molecules binding at any of the multiple regulatory sites on the molecular surface of a protein kinase may stabilize or disrupt the corresponding interaction, leading to consequent modulation of the kinase cellular activity. As such, each of these sites represents a potential drug target. Even targeting sites outside the immediate ATP site, the so-called exosites, may cause desirable biological effects through an allosteric mechanism. Targeting exosites can alleviate adverse effects and toxicity that is common when ATP-site compounds bind promiscuously to many other types of kinases. In this study we have identified, catalogued, and annotated all potentially druggable exosites on the protein kinase domains within the existing structural human kinome. We then priority-ranked these exosites by those most amenable to drug design. In order to identify pockets that are either consistent across the kinome, or unique and specific to a particular structure, we have also implemented a normalized representation of all pockets, and displayed these graphically. Finally, we have built a database and designed a web-based interface for users interested in accessing the 3-dimensional representations of these pockets. We envision this information will assist drug discovery efforts searching for untargeted binding pockets in the human kinome.
Topics: Adenosine Triphosphate; Binding Sites; Drug Design; Genome, Human; Humans; Protein Binding; Protein Domains; Protein Kinases; Surface Properties
PubMed: 31925639
DOI: 10.1007/s10822-019-00276-y -
Seminars in Cell & Developmental Biology Jan 2021Receptor Interacting Protein Kinases (RIPKs) are a family of Ser/Thr/Tyr kinases whose functions, regulation and pathophysiologic roles have remained an enigma for a... (Review)
Review
Receptor Interacting Protein Kinases (RIPKs) are a family of Ser/Thr/Tyr kinases whose functions, regulation and pathophysiologic roles have remained an enigma for a long time. In recent years, these proteins garnered significant interest due to their roles in regulating a variety of host defense functions including control of inflammatory gene expression, different forms of cell death, and cutaneous and intestinal barrier functions. In addition, there is accumulating evidence that while these kinases seemingly follow typical kinase blueprints, their functioning in cells can take forms that are atypical for protein kinases. Lastly, while these kinases generally belong to distinct areas of innate immune regulation, there are emerging overarching themes that may unify the functions of this kinase family. Our review seeks to discuss the biology of RIPKs, and how typical and atypical features of this family informs the activity of a rapidly growing repertoire of RIPK inhibitors.
Topics: Humans; Protein Kinases; Receptor-Interacting Protein Serine-Threonine Kinases
PubMed: 32732131
DOI: 10.1016/j.semcdb.2020.06.014 -
Toxins Dec 2021Crotalphine (CRP) is a structural analogue to a peptide that was first identified in the crude venom from the South American rattlesnake . This peptide induces a potent...
Crotalphine (CRP) is a structural analogue to a peptide that was first identified in the crude venom from the South American rattlesnake . This peptide induces a potent and long-lasting antinociceptive effect that is mediated by the activation of peripheral opioid receptors. The opioid receptor activation regulates a variety of intracellular signaling, including the mitogen-activated protein kinase (MAPK) pathway. Using primary cultures of sensory neurons, it was demonstrated that crotalphine increases the level of activated ERK1/2 and JNK-MAPKs and this increase is dependent on the activation of protein kinase Cζ (PKCζ). However, whether PKCζ-MAPK signaling is critical for crotalphine-induced antinociception is unknown. Here, we biochemically demonstrated that the systemic crotalphine activates ERK1/2 and JNK and decreases the phosphorylation of p38 in the lumbar spinal cord. The in vivo pharmacological inhibition of spinal ERK1/2 and JNK, but not of p38, blocks the antinociceptive effect of crotalphine. Of interest, the administration of a PKCζ pseudosubstrate (PKCζ inhibitor) prevents crotalphine-induced ERK activation in the spinal cord, followed by the abolishment of crotalphine-induced analgesia. Together, our results demonstrate that the PKCζ-ERK signaling pathway is involved in crotalphine-induced analgesia. Our study opens a perspective for the PKCζ-MAPK axis as a target for pain control.
Topics: Animals; Behavior, Animal; Gene Expression Regulation, Enzymologic; Mitogen-Activated Protein Kinases; Pain; Peptides; Protein Kinase C; Rats; Rats, Wistar; Signal Transduction
PubMed: 34941749
DOI: 10.3390/toxins13120912 -
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 -
Nature Communications Aug 2021Dietary interventions such as intermittent fasting (IF) have emerged as an attractive strategy for cancer therapies; therefore, understanding the underlying molecular...
Dietary interventions such as intermittent fasting (IF) have emerged as an attractive strategy for cancer therapies; therefore, understanding the underlying molecular mechanisms is pivotal. Here, we find SIRT7 decline markedly attenuates the anti-tumor effect of IF. Mechanistically, AMP-activated protein kinase (AMPK) phosphorylating SIRT7 at T263 triggers further phosphorylation at T255/S259 by glycogen synthase kinase 3β (GSK3β), which stabilizes SIRT7 by decoupling E3 ligase UBR5. SIRT7 hyperphosphorylation achieves anti-tumor activity by disrupting the SKP2-SCF E3 ligase, thus preventing SKP2-mediated K63-linked AKT polyubiquitination and subsequent activation. In contrast, GSK3β-SIRT7 axis is inhibited by EGF/ERK2 signaling, with ERK2 inactivating GSK3β, thus accelerating SIRT7 degradation. Unfavorably, glucose deprivation or chemotherapy hijacks the GSK3β-SIRT7 axis via ERK2, thus activating AKT and ensuring survival. Notably, Trametinib, an FDA-approved MEK inhibitor, enhances the efficacy of combination therapy with doxorubicin and IF. Overall, we have revealed the GSK3β-SIRT7 axis that must be fine-tuned in the face of the energetic and oncogenic stresses in malignancy.
Topics: AMP-Activated Protein Kinase Kinases; Animals; Combined Modality Therapy; Doxorubicin; Fasting; Female; Glycogen Synthase Kinase 3 beta; Humans; Male; Mice; Mice, Inbred BALB C; Mitogen-Activated Protein Kinase 1; Neoplasms; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Proteolysis; Sirtuins
PubMed: 34433808
DOI: 10.1038/s41467-021-25274-3 -
International Journal of Molecular... Dec 2021Apoptosis signal-regulating kinase (ASK) 1, a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, modulates diverse responses to oxidative and... (Review)
Review
Apoptosis signal-regulating kinase (ASK) 1, a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, modulates diverse responses to oxidative and endoplasmic reticulum (ER) stress and calcium influx. As a crucial cellular stress sensor, ASK1 activates c-Jun N-terminal kinases (JNKs) and p38 MAPKs. Their excessive and sustained activation leads to cell death, inflammation and fibrosis in various tissues and is implicated in the development of many neurological disorders, such as Alzheimer's, Parkinson's and Huntington disease and amyotrophic lateral sclerosis, in addition to cardiovascular diseases, diabetes and cancer. However, currently available inhibitors of JNK and p38 kinases either lack efficacy or have undesirable side effects. Therefore, targeted inhibition of their upstream activator, ASK1, stands out as a promising therapeutic strategy for treating such severe pathological conditions. This review summarizes recent structural findings on ASK1 regulation and its role in various diseases, highlighting prospects for ASK1 inhibition in the treatment of these pathologies.
Topics: 14-3-3 Proteins; Animals; Apoptosis; Apoptosis Regulatory Proteins; Endoplasmic Reticulum Stress; Humans; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase Kinase 5; MAP Kinase Kinase Kinases; MAP Kinase Signaling System; Oxidation-Reduction; Oxidative Stress; Phosphorylation; Protein Interaction Maps; Signal Transduction; p38 Mitogen-Activated Protein Kinases
PubMed: 34948191
DOI: 10.3390/ijms222413395 -
IUBMB Life Jun 2020The spectrum of kinase alterations displays distinct functional characteristics and requires kinase mutation-oriented strategies for therapeutic interference. Besides...
The spectrum of kinase alterations displays distinct functional characteristics and requires kinase mutation-oriented strategies for therapeutic interference. Besides phosphotransferase activity, protein abundance, and intermolecular interactions, particular patient-mutations promote pathological kinase conformations. Despite major advances in identifying lead molecules targeting clinically relevant oncokinase functions, still many kinases are neglected and not part of drug discovery efforts. One explanation is attributed to challenges in tracking kinase activities. Chemical probes are needed to functionally annotate kinase functions, whose activities may not always depend on catalyzing phospho-transfer. Such non-catalytic kinase functions are related to transitions of full-length kinase conformations. Recent findings underline that cell-based reporter systems can be adapted to record conformation changes of kinases. Here, we discuss the possible applications of an extendable kinase conformation (KinCon) reporter toolbox for live-cell recording of kinase states. KinCon is a genetically encoded bioluminescence-based biosensor platform, which can be subjected for measurements of conformation dynamics of mutated kinases upon small molecule inhibitor exposure. We hypothesize that such biosensors can be utilized to delineate the molecular modus operandi for kinase and pseudokinase regulation. This should pave the path for full-length kinase-targeted drug discovery efforts aiming to identify single and combinatory kinase inhibitor therapies with increased specificity and efficacy.
Topics: Biosensing Techniques; Genes, Reporter; Humans; Luciferases; Luminescent Measurements; Molecular Biology; Protein Conformation; Protein Kinases
PubMed: 32027084
DOI: 10.1002/iub.2241 -
Journal of Neurochemistry Nov 2021Morphine is a potent opioid analgesic with high propensity for the development of antinociceptive tolerance. Morphine antinociception and tolerance are partially...
Morphine is a potent opioid analgesic with high propensity for the development of antinociceptive tolerance. Morphine antinociception and tolerance are partially regulated by the midbrain ventrolateral periaqueductal gray (vlPAG). However, the majority of research evaluating mu-opioid receptor signaling has focused on males. Here, we investigate kinase activation and localization patterns in the vlPAG following acute and chronic morphine treatment in both sexes. Male and female mice developed rapid antinociceptive tolerance to morphine (10 mg/kg i.p.) on the hot plate assay, but tolerance did not develop in males on the tail flick assay. Quantitative fluorescence immunohistochemistry was used to map and evaluate the activation of extracellular signal-regulated kinase 1/2 (ERK 1/2), protein kinase-C (PKC), and protein kinase-A (PKA). We observed significantly greater phosphorylated ERK 1/2 in the vlPAG of chronic morphine-treated animals which co-localized with the endosomal marker, Eea1. We note that pPKC is significantly elevated in the vlPAG of both sexes following chronic morphine treatment. We also observed that although PKA activity is elevated following chronic morphine treatment in both sexes, there is a significant reduction in the nuclear translocation of its phosphorylated substrate. Taken together, this study demonstrates increased activation of ERK 1/2, PKC, and PKA in response to repeated morphine treatment. The study opens avenues to explore the impact of chronic morphine treatment on G-protein signaling and kinase nuclear transport.
Topics: Animals; Female; Male; Mice; Cyclic AMP-Dependent Protein Kinases; Drug Tolerance; Enzyme Induction; MAP Kinase Signaling System; Mice, Inbred C57BL; Morphine; Pain Measurement; Periaqueductal Gray; Protein Kinase C; Protein Kinases; Protein Transport; Sex Characteristics; Vesicular Transport Proteins
PubMed: 34499746
DOI: 10.1111/jnc.15506