scholarly journals The serine/threonine/tyrosine kinase STY46 defends against hordeivirus infection by phosphorylating γb protein

2021 ◽  
Author(s):  
Xuan Zhang ◽  
Xueting Wang ◽  
Kai Xu ◽  
Zhihao Jiang ◽  
Kai Dong ◽  
...  
Keyword(s):  
Stress Responses ◽  
Kinase Activity ◽  
Host Protein ◽  
Virus Infectivity ◽  
Post Translational Modification ◽  
Antiviral Role ◽  
Coevolutionary Arms Race

Abstract Protein phosphorylation is a common post-translational modification that frequently occurs during plant–virus interaction. Host protein kinases often regulate virus infectivity and pathogenicity by phosphorylating viral proteins. The Barley stripe mosaic virus (BSMV) γb protein plays versatile roles in virus infection and the coevolutionary arms race between plant defense and viral counter-defense. Here, we identified that the autophosphorylated cytosolic serine/threonine/tyrosine (STY) protein kinase 46 of Nicotiana benthamiana (NbSTY46) phosphorylates and directly interacts with the basic motif domain (aa 19–47) of γb in vitro and in vivo. Overexpression of wild-type NbSTY46, either transiently or transgenically, suppresses BSMV replication and ameliorates viral symptoms, whereas silencing of NbSTY46 leads to increased viral replication and exacerbated symptom. Moreover, the antiviral role of NbSTY46 requires its kinase activity, as the NbSTY46T436A mutant, lacking kinase activity, not only loses the ability to phosphorylate and interact with γb but also fails to impair BSMV infection when expressed in plants. NbSTY46 could also inhibit the replication of Lychnis ringspot virus, another chloroplast-replicating hordeivirus. In summary, we report a function of the cytosolic kinase STY46 in defending against plant viral infection by phosphorylating a viral protein in addition to its basal function in plant growth, development, and abiotic stress responses.

scholarly journals Cks1 Is Required for G1Cyclin–Cyclin-Dependent Kinase Activity in Budding Yeast

2000 ◽  
Vol 20 (16) ◽  
pp. 5858-5864 ◽  
Author(s):  
Gregory J. Reynard ◽  
William Reynolds ◽  
Rati Verma ◽  
Raymond J. Deshaies
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Budding Yeast ◽  
Protein Kinase Activity ◽  
Cyclin Dependent Kinase ◽  
Multiple Substrates ◽  
Cell Extracts

ABSTRACT p13suc1 (Cks) proteins have been implicated in the regulation of cyclin-dependent kinase (CDK) activity. However, the mechanism by which Cks influences the function of cyclin-CDK complexes has remained elusive. We show here that Cks1 is required for the protein kinase activity of budding yeast G1 cyclin-CDK complexes. Cln2 and Cdc28 subunits coexpressed in baculovirus-infected insect cells fail to exhibit protein kinase activity towards multiple substrates in the absence of Cks1. Cks1 can both stabilize Cln2-Cdc28 complexes and activate intact complexes in vitro, suggesting that it plays multiple roles in the biogenesis of active G1cyclin-CDK complexes. In contrast, Cdc28 forms stable, active complexes with the B-type cyclins Clb4 and Clb5 regardless of whether Cks1 is present. The levels of Cln2-Cdc28 and Cln3-Cdc28 protein kinase activity are severely reduced in cks1-38 cell extracts. Moreover, phosphorylation of G1 cyclins, which depends on Cdc28 activity, is reduced in cks1-38 cells. The role of Cks1 in promoting G1 cyclin-CDK protein kinase activity both in vitro and in vivo provides a simple molecular rationale for the essential role of CKS1 in progression through G1 phase in budding yeast.

scholarly journals Pathogenic mutations in LRRK2 sequester Rab8a to damaged lysosomes and regulate transferrin-mediated iron uptake in microglia

2020 ◽  
Author(s):  
Adamantios Mamais ◽  
Natalie Landeck ◽  
Rebekah G. Langston ◽  
Luis Bonet-Ponce ◽  
Nathan Smith ◽  
...  
Keyword(s):  
Iron Uptake ◽  
Kinase Activity ◽  
Small Gtpase ◽  
Kinase Substrate ◽  
Lrrk2 Kinase ◽  
Effect Of Pd ◽  
Lrrk2 Kinase Activity

AbstractMutations in leucine-rich repeat kinase 2 (LRRK2) cause autosomal dominant Parkinson’s disease (PD) while polymorphic LRRK2 variants are associated with sporadic PD. PD-linked mutations increase LRRK2 kinase activity and induce neurotoxicity in vitro and in vivo. The small GTPase Rab8a is a LRRK2 kinase substrate and is involved in receptor-mediated recycling and endocytic trafficking of transferrin, but the effect of PD-linked LRRK2 mutations on the function of Rab8a are poorly understood. Here, we show that gain-of-function mutations in LRRK2 induce sequestration of endogenous Rab8a into lysosomes in cells while pharmacological inhibition of LRRK2 kinase activity reverses this phenotype. Furthermore, we show that LRRK2 mutations drive accumulation of endocytosed transferrin into Rab8a-positive lysosomes leading to a dysregulation of iron transport. LRRK2 has been nominated as an integral part of cellular responses downstream of proinflammatory signals and is activated in microglia in post-mortem PD tissue. Here, we show that iPSC-derived microglia from patients carrying the most common LRRK2 mutation, G2019S, mistraffic transferrin to lysosomes proximal to the nucleus in proinflammatory conditions. Furthermore, G2019S knock-in mice show significant increase in iron deposition in microglia following intrastriatal LPS injection compared to wild type mice, accompanied by striatal accumulation of ferritin. Our data support a role of LRRK2 in modulating iron uptake and storage in response to proinflammatory stimuli in microglia.

scholarly journals Role of the (Mn)superoxide dismutase of Enterococcus faecalis in the in vitro interaction with microglia

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1816-1822 ◽  
Author(s):  
Samuele Peppoloni ◽  
Brunella Posteraro ◽  
Bruna Colombari ◽  
Lidia Manca ◽  
Axel Hartke ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Enterococcus Faecalis ◽  
Stress Responses ◽  
Peritoneal Macrophages ◽  
Infection Process ◽  
Microglial Cells ◽  
Infection Model

Enterococcus faecalis is a significant human pathogen worldwide and is responsible for severe nosocomial and community-acquired infections. Although enterococcal meningitis is rare, mortality is considerable, reaching 21 %. Nevertheless, the pathogenetic mechanisms of this infection remain poorly understood, even though the ability of E. faecalis to avoid or survive phagocytic attack in vivo may be very important during the infection process. We previously showed that the manganese-cofactored superoxide dismutase (MnSOD) SodA of E. faecalis was implicated in oxidative stress responses and, interestingly, in the survival within mouse peritoneal macrophages using an in vivo–in vitro infection model. In the present study, we investigated the role of MnSOD in the interaction of E. faecalis with microglia, the brain-resident macrophages. By using an in vitro infection model, murine microglial cells were challenged in parallel with the wild-type strain JH2-2 and its isogenic sodA deletion mutant. While both strains were phagocytosed by microglia efficiently and to a similar extent, the ΔsodA mutant was found to be significantly more susceptible to microglial killing than JH2-2, as assessed by the antimicrobial protection assay. In addition, a significantly higher percentage of acidic ΔsodA-containing phagosomes was found and these also underwent enhanced maturation as determined by the expression of endolysosomal markers. In conclusion, these results show that the MnSOD of E. faecalis contributes to survival of the bacterium in microglial cells by influencing their antimicrobial activity, and this could even be important for intracellular killing in neutrophils and thus for E. faecalis pathogenesis.

scholarly journals OsnR is an autoregulatory negative transcription factor controlling redox-dependent stress responses in Corynebacterium glutamicum

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Haeri Jeong ◽  
Younhee Kim ◽  
Heung-Shick Lee
Keyword(s):  
Oxidative Stress ◽  
Corynebacterium Glutamicum ◽  
Stress Responses ◽  
Promoter Region ◽  
Underlying Mechanism ◽  
In Vitro Assays ◽  
Expression Of Genes

Abstract Background Corynebacterium glutamicum is used in the industrial production of amino acids and nucleotides. During the course of fermentation, C. glutamicum cells face various stresses and employ multiple regulatory genes to cope with the oxidative stress. The osnR gene plays a negative regulatory role in redox-dependent oxidative-stress responses, but the underlying mechanism is not known yet. Results Overexpression of the osnR gene in C. glutamicum affected the expression of genes involved in the mycothiol metabolism. ChIP-seq analysis revealed that OsnR binds to the promoter region of multiple genes, including osnR and cg0026, which seems to function in the membrane-associated redox metabolism. Studies on the role of the osnR gene involving in vitro assays employing purified OsnR proteins and in vivo physiological analyses have identified that OsnR inhibits the transcription of its own gene. Further, oxidant diamide stimulates OsnR-binding to the promoter region of the osnR gene. The genes affected by the overexpression of osnR have been found to be under the control of σH. In the osnR-overexpressing strain, the transcription of sigH is significantly decreased and the stimulation of sigH transcription by external stress is lost, suggesting that osnR and sigH form an intimate regulatory network. Conclusions Our study suggests that OsnR not only functions as a transcriptional repressor of its own gene and of those involved in redox-dependent stress responses but also participates in the global transcriptional regulation by controlling the transcription of other master regulators, such as sigH.

scholarly journals Inhibition of SENP2-mediated Akt deSUMOylation promotes cardiac regeneration via activating Akt pathway

2021 ◽  
Vol 135 (6) ◽  
pp. 811-828
Author(s):  
Yijin Chen ◽  
Tong Xu ◽  
Mengsha Li ◽  
Chuling Li ◽  
Yusheng Ma ◽  
...  
Keyword(s):  
Heart Development ◽  
Cardiac Regeneration ◽  
Akt Pathway ◽  
Post Translational Modification ◽  
Specific Protease ◽  
Differentiation And Proliferation ◽  
Novel Therapeutic Strategies

AbstractPost-translational modification (PTM) by small ubiquitin-like modifier (SUMO) is a key regulator of cell proliferation and can be readily reversed by a family of SUMO-specific proteases (SENPs), making SUMOylation an ideal regulatory mechanism for developing novel therapeutic strategies for promoting a cardiac regenerative response. However, the role of SUMOylation in cardiac regeneration remains unknown. In the present study, we assessed whether targeting protein kinase B (Akt) SUMOylation can promote cardiac regeneration. Quantitative PCR and Western blotting results showed that small ubiquitin-like modifier-specific protease 2 (SENP2) is up-regulated during postnatal heart development. SENP2 deficiency promoted P7 and adult cardiomyocyte (CM) dedifferentiation and proliferation both in vitro and in vivo. Mice with SENP2 deficiency exhibited improved cardiac function after MI due to CM proliferation and angiogenesis. Mechanistically, the loss of SENP2 up-regulated Akt SUMOylation levels and increased Akt kinase activity, leading to a decrease in GSK3β levels and subsequently promoting CM proliferation and angiogenesis. In summary, inhibition of SENP2-mediated Akt deSUMOylation promotes CM differentiation and proliferation by activating the Akt pathway. Our results provide new insights into the role of SUMOylation in cardiac regeneration.

scholarly journals SENP Proteases as Potential Targets for Cancer Therapy

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2059
Author(s):  
Paulina Tokarz ◽  
Katarzyna Woźniak
Keyword(s):  
Cancer Cells ◽  
Therapeutic Potential ◽  
Cysteine Proteases ◽  
Covalent Attachment ◽  
Post Translational Modification ◽  
Small Molecular Weight ◽  
Aberrant Expression

SUMOylation is a reversible post-translational modification (PTM) involving a covalent attachment of small ubiquitin-related modifier (SUMO) proteins to substrate proteins. SUMO-specific proteases (SENPs) are cysteine proteases with isopeptidase activity facilitating the de-conjugation of SUMO proteins and thus participating in maintaining the balance between the pools of SUMOylated and unSUMOylated proteins and in SUMO recycling. Several studies have reported that SENPs’ aberrant expression is associated with the development and progression of cancer. In this review, we will discuss the role of SENPs in the pathogenesis of cancer, focusing on DNA repair and the cell cycle—cellular pathways malfunctioning in most cancer cells. The plausible role of SENPs in carcinogenesis resulted in the design and development of their inhibitors, including synthetic protein-based, peptide-based, and small molecular weight inhibitors, as well as naturally occurring compounds. Computational methods including virtual screening have been implemented to identify a number of lead structures in recent years. Some inhibitors suppressed the proliferation of prostate cancer cells in vitro and in vivo, confirming that SENPs are suitable targets for anti-cancer treatment. Further advances in the development of SENP-oriented inhibitors are anticipated toward SENP isoform-specific molecules with therapeutic potential.

scholarly journals Reciprocal Regulation of PASTA Kinase Signaling by Differential Modification

2019 ◽  
Vol 201 (10) ◽  
Author(s):  
Benjamin D. Labbe ◽  
Cherisse L. Hall ◽  
Stephanie L. Kellogg ◽  
Yao Chen ◽  
Olivia Koehn ◽  
...  
Keyword(s):  
Cell Wall ◽  
Antibiotic Resistance ◽  
Kinase Activity ◽  
Cell Envelope ◽  
Activation Loop ◽  
Intrinsic Resistance ◽  
Content Type

ABSTRACTTransmembrane Ser/Thr kinases containing extracellular PASTA (penicillin-binding protein [PBP]andSer/Thr-associated) domains are ubiquitous amongActinobacteriaandFirmicutesspecies. Such PASTA kinases regulate critical bacterial processes, including antibiotic resistance, cell division, cell envelope homeostasis, and virulence, and are sometimes essential for viability. Previous studies of purified PASTA kinase fragments revealed they are capable of autophosphorylationin vitro, typically at multiple sites on the kinase domain. Autophosphorylation of a specific structural element of the kinase known as the activation loop is thought to enhance kinase activity in response to stimuli. However, the role of kinase phosphorylation at other sites is largely unknown. Moreover, the mechanisms by which PASTA kinases are deactivated once their stimulus has diminished are poorly understood.Enterococcus faecalisis a Gram-positive intestinal bacterium and a major antibiotic-resistant opportunistic pathogen. InE. faecalis, the PASTA kinase IreK drives intrinsic resistance to cell wall-active antimicrobials, and such antimicrobials trigger enhanced phosphorylation of IreKin vivo. Here we identify multiple sites of phosphorylation on IreK and evaluate their functionin vivoandin vitro. While phosphorylation of the IreK activation loop is required for kinase activity, we found that phosphorylation at a site distinct from the activation loop reciprocally modulates IreK activityin vivo, leading to diminished activity (and diminished antimicrobial resistance). Moreover, this site is important for deactivation of IreKin vivoupon removal of an activating stimulus. Our results are consistent with a model in which phosphorylation of IreK at distinct sites reciprocally regulates IreK activityin vivoto promote adaptation to cell wall stresses.IMPORTANCETransmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous amongActinobacteriaandFirmicutesspecies and regulate critical processes, including antibiotic resistance, cell division, and cell envelope homeostasis. Previous studies of PASTA kinase fragments revealed autophosphorylation at multiple sites. However, the functional role of autophosphorylation and the relative impacts of phosphorylation at distinct sites are poorly understood. The PASTA kinase ofEnterococcus faecalis, IreK, regulates intrinsic resistance to antimicrobials. Here we identify multiple sites of phosphorylation on IreK and show that modification of IreK at distinct sites reciprocally regulates IreK activity and antimicrobial resistancein vivo. Thus, these results provide new insights into the mechanisms by which PASTA kinases can regulate critical physiological processes in a wide variety of bacterial species.

scholarly journals PINK1 kinase dysfunction triggers neurodegeneration in the primate brain without impacting mitochondrial homeostasis

2021 ◽  
Author(s):  
Weili Yang ◽  
Xiangyu Guo ◽  
Zhuchi Tu ◽  
Xiusheng Chen ◽  
Rui Han ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mitochondrial Function ◽  
Kinase Activity ◽  
Mitochondrial Protein ◽  
Neuronal Function ◽  
Mitochondrial Homeostasis ◽  
Primate Brain

AbstractIn vitro studies have established the prevalent theory that the mitochondrial kinase PINK1 protects neurodegeneration by removing damaged mitochondria in Parkinson’s disease (PD). However, difficulty in detecting endogenous PINK1 protein in rodent brains and cell lines has prevented the rigorous investigation of the in vivo role of PINK1. Here we report that PINK1 kinase form is selectively expressed in the human and monkey brains. CRISPR/Cas9-mediated deficiency of PINK1 causes similar neurodegeneration in the brains of fetal and adult monkeys as well as cultured monkey neurons without affecting mitochondrial protein expression and morphology. Importantly, PINK1 mutations in the primate brain and human cells reduce protein phosphorylation that is important for neuronal function and survival. Our findings suggest that PINK1 kinase activity rather than its mitochondrial function is essential for the neuronal survival in the primate brains and that its kinase dysfunction could be involved in the pathogenesis of PD.

scholarly journals Development of a mass-spectrometry based method for the identification of the in vivo whole blood and plasma ADP-ribosylomes

2020 ◽  
Author(s):  
Stephanie C. Lüthi ◽  
Anna Howald ◽  
Kathrin Nowak ◽  
Robert Graage ◽  
Giody Bartolomei ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Whole Blood ◽  
Sus Scrofa ◽  
Plasma Proteins ◽  
Post Translational Modification ◽  
Blood Samples ◽  
Adp Ribosylation

ABSTRACTBlood and plasma proteins are heavily investigated as biomarkers for different diseases. However, the post-translational modification states of these proteins are rarely analyzed since blood contains many enzymes that rapidly remove these modification after sampling. In contrast to the well-described role of protein ADP-ribosylation in cells and organs, its role in blood remains mostly uncharacterized. Here, we discovered that plasma phosphodiesterases and/or ADP-ribosylhydrolases rapidly demodify in vitro ADP-ribosylated proteins. Thus, to identify the in vivo whole blood and plasma ADP-ribosylomes, we established a novel mass-spectrometry based workflow that was applied to blood samples collected from LPS-treated pigs (Sus scrofa), which serves as a model for human systemic inflammatory response syndrome. These analyses identified 60 ADP-ribosylated proteins, 17 of which were ADP-ribosylated plasma proteins. This new protocol provides an important step forward for the rapidly developing field of ADP-ribosylation and defines the blood and plasma ADP-ribosylomes under both healthy and disease conditions.

scholarly journals Ligand-dependent kinase activity of MERTK drives efferocytosis in human iPSC-derived macrophages

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Florian Wanke ◽  
Simon Gutbier ◽  
Anna Rümmelin ◽  
Malte Steinberg ◽  
Lindsey D. Hughes ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Critical Role ◽  
Peritoneal Macrophages ◽  
Apoptotic Cells ◽  
Surface Receptors ◽  
Natural Ligand ◽  
Human Ipsc

AbstractRemoval of apoptotic cells by phagocytes (also called efferocytosis) is a crucial process for tissue homeostasis. Professional phagocytes express a plethora of surface receptors enabling them to sense and engulf apoptotic cells, thus avoiding persistence of dead cells and cellular debris and their consequent effects. Dysregulation of efferocytosis is thought to lead to secondary necrosis and associated inflammation and immune activation. Efferocytosis in primarily murine macrophages and dendritic cells has been shown to require TAM RTKs, with MERTK and AXL being critical for clearance of apoptotic cells. The functional role of human orthologs, especially the exact contribution of each individual receptor is less well studied. Here we show that human macrophages differentiated in vitro from iPSC-derived precursor cells express both AXL and MERTK and engulf apoptotic cells. TAM RTK agonism by the natural ligand growth-arrest specific 6 (GAS6) significantly enhanced such efferocytosis. Using a newly-developed mouse model of kinase-dead MERTK, we demonstrate that MERTK kinase activity is essential for efferocytosis in peritoneal macrophages in vivo. Moreover, human iPSC-derived macrophages treated in vitro with blocking antibodies or small molecule inhibitors recapitulated this observation. Hence, our results highlight a conserved MERTK function between mice and humans, and the critical role of its kinase activity in homeostatic efferocytosis.

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