scholarly journals Phosphorylation of multiple proteins involved in ciliogenesis by Tau Tubulin kinase 2

2019 ◽  
Author(s):  
Ondrej Bernatik ◽  
Petra Pejskova ◽  
David Vyslouzil ◽  
Katerina Hanakova ◽  
Zbynek Zdrahal ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Kinase Activity ◽  
Consensus Sequence ◽  
Limited Information ◽  
Assembly Pathway ◽  
Cilia Formation ◽  
Functional Relevance ◽  
Insight Into

AbstractPrimary cilia (PC) are organelles necessary for proper implementation of developmental and homeostasis processes. To initiate their assembly, coordinated actions of multiple proteins are needed. Tau tubulin kinase 2 (TTBK2) is a key player in the cilium assembly pathway, controlling final step of cilia initiation. The function of TTBK2 in ciliogenesisis is critically dependent on its kinase activity, however, precise mechanism of TTBK2 action is so far incompletely understood, due to very limited information about its relevant substrates. In this study we identify CEP83, CEP89, CCDC92, Rabin8 and DVL3 as substrates of TTBK2 kinase activity. Further, we characterise a set of phosphosites of the newly identified substrates and CEP164, induced by TTBK2in vitroandin vivo. Intriguingly, we further show that identified TTBK2 phosphosites and consensus sequence delineated from those are distinct from motifs previously assigned to TTBK2. Finally, we address functional relevance of selected phosphorylations of CEP164 and provide evidence that the examined TTBK2-induced phosphorylations of CEP164 are relevant for the process of cilia formation. In summary, our work provides important insight into substrates-TTBK2 kinase relationship and suggests that phosphorylation of substrates on multiple sites by TTBK2 is probably involved in the control of ciliogenesis in human cells.

scholarly journals TOR signaling modulates Cdk8-dependent GAL gene expression in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Nicole Hawe ◽  
Konstantin Mestnikov ◽  
Riley Horvath ◽  
Mariam Eji-Lasisi ◽  
Cindy Lam ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Polymerase Ii ◽  
Nuclear Localization ◽  
Kinase Activity ◽  
Mediator Complex ◽  
Tor Signaling ◽  
A Subunit ◽  
Insight Into

AbstractCdk8 of the RNA Polymerase II mediator complex regulates genes by phosphorylating sequence specific transcription factors. Despite conserved importance for eukaryotic transcriptional regulation, the signals regulating Cdk8 are unknown. Full induction of the yeast GAL genes requires phosphorylation of Gal4 by Cdk8, and we exploited this requirement for growth of gal3 yeast on galactose to identify mutants affecting Cdk8 activity. Several mutants from the screen produced defects in TOR signaling. A mutant designated gal four throttle (gft) 1, gft1, was identified as an allele of hom3, encoding aspartokinase. Defects in gft1/ hom3 caused hypersensitivity to rapamycin, and constitutive nuclear localization of Gat1. Furthermore, mutations of tor1 or tco89, encoding TORC1 components, also prevented GAL expression in gal3 yeast, and tco89 was determined to be allelic to gft7. Disruption of cdc55, encoding a subunit of PP2A regulated by TOR signaling, suppressed the effect of gft1/ hom3, gft7/ tco89, and tor1 mutations on GAL expression in gal3 yeast, but not of cdk8/ srb10 disruptions or Gal4 S699A mutation. Mutations of gft1/ hom3 and tor1 did not affect kinase activity of Cdk8 in vitro, but caused loss of Gal4 phosphorylation in vivo. These observations demonstrate that TOR signaling regulates GAL induction through the activity of PP2A/ Cdc55, and are consistent with the contention that Cdk8-dependent phosphorylation of Gal4 S699 is opposed by PP2A/ Cdc55 dephosphorylation. These results provide insight into how induction of transcription by a specific inducer can be modulated by global nutritional signals through regulation of Cdk8-dependent phosphorylation.

scholarly journals In Silico Predicted Antifungal Peptides: In Vitro and In Vivo Anti-Candida Activity

2021 ◽  
Vol 7 (6) ◽  
pp. 439
Author(s):  
Tecla Ciociola ◽  
Walter Magliani ◽  
Tiziano De Simone ◽  
Thelma A. Pertinhez ◽  
Stefania Conti ◽  
...  
Keyword(s):  
In Silico ◽  
Mammalian Cells ◽  
Galleria Mellonella ◽  
Ex Vivo ◽  
Consensus Sequence ◽  
In Silico Analysis ◽  
Significant Activity ◽  
Synthetic Antibody

It has been previously demonstrated that synthetic antibody-derived peptides could exert a significant activity in vitro, ex vivo, and/or in vivo against microorganisms and viruses, as well as immunomodulatory effects through the activation of immune cells. Based on the sequence of previously described antibody-derived peptides with recognized antifungal activity, an in silico analysis was conducted to identify novel antifungal candidates. The present study analyzed the candidacidal and structural properties of in silico designed peptides (ISDPs) derived by amino acid substitutions of the parent peptide KKVTMTCSAS. ISDPs proved to be more active in vitro than the parent peptide and all proved to be therapeutic in Galleria mellonella candidal infection, without showing toxic effects on mammalian cells. ISDPs were studied by circular dichroism spectroscopy, demonstrating different structural organization. These results allowed to validate a consensus sequence for the parent peptide KKVTMTCSAS that may be useful in the development of novel antimicrobial molecules.

scholarly journals Plant-Derived Extracellular Vesicles: Current Findings,Challenges, and Future Applications

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 411
Author(s):  
Nader Kameli ◽  
Anya Dragojlovic-Kerkache ◽  
Paul Savelkoul ◽  
Frank R. Stassen
Keyword(s):  
Human Health ◽  
Extracellular Vesicles ◽  
Preliminary Results ◽  
In Vivo Experiments ◽  
Health And Disease ◽  
Conducting Research ◽  
Protocol Standardization ◽  
Insight Into

In recent years, plant-derived extracellular vesicles (PDEVs) have gained the interest of many experts in fields such as microbiology and immunology, and research in this field has exponentially increased. These nano-sized particles have provided researchers with a number of interesting findings, making their application in human health and disease very promising. Both in vitro and in vivo experiments have shown that PDEVs can exhibit a multitude of effects, suggesting that these vesicles may have many potential future applications, including therapeutics and nano-delivery of compounds. While the preliminary results are promising, there are still some challenges to face, such as a lack of protocol standardization, as well as knowledge gaps that need to be filled. This review aims to discuss various aspects of PDEV knowledge, including their preliminary findings, challenges, and future uses, giving insight into the complexity of conducting research in this field.

scholarly journals Mechanistic physiology-based pharmacokinetic modeling to elucidate vincristine-induced peripheral neuropathy following treatment with novel kinase inhibitors

2021 ◽  
Author(s):  
Venkatesh Pilla Reddy ◽  
Adrian J. Fretland ◽  
Diansong Zhou ◽  
Shringi Sharma ◽  
Buyun Chen ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Kinase Inhibitors ◽  
Pbpk Model ◽  
Model Development ◽  
Limited Information ◽  
Time Curve ◽  
Btk Inhibitor ◽  
Chop Therapy

Abstract Purpose Limited information is available regarding the drug–drug interaction (DDI) potential of molecular targeted agents and rituximab plus cyclophosphamide, doxorubicin (hydroxydaunorubicin), vincristine (Oncovin), and prednisone (R-CHOP) therapy. The addition of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib to R-CHOP therapy results in increased toxicity versus R-CHOP alone, including higher incidence of peripheral neuropathy. Vincristine is a substrate of P-glycoprotein (P-gp, ABCB1); drugs that inhibit P-gp could potentially cause increased toxicity when co-administered with vincristine through DDI. While the combination of the BTK inhibitor acalabrutinib and R-CHOP is being explored clinically, the DDI potential between these therapies is unknown. Methods A human mechanistic physiology-based pharmacokinetic (PBPK) model of vincristine following intravenous dosing was developed to predict potential DDI interactions with combination therapy. In vitro absorption, distribution, metabolism, and excretion and in vivo clinical PK parameters informed PBPK model development, which was verified by comparing simulated vincristine concentrations with observed clinical data. Results While simulations suggested no DDI between vincristine and ibrutinib or acalabrutinib in plasma, simulated vincristine exposure in muscle tissue was increased in the presence of ibrutinib but not acalabrutinib. Extrapolation of the vincristine mechanistic PBPK model to other P-gp substrates further suggested DDI risk when ibrutinib (area under the concentration–time curve [AUC] ratio: 1.8), but not acalabrutinib (AUC ratio: 0.92), was given orally with venetoclax or digoxin. Conclusion Overall, these data suggest low DDI risk between acalabrutinib and P-gp substrates with negligible increase in the potential risk of vincristine-induced peripheral neuropathy when acalabrutinib is added to R-CHOP therapy.

scholarly journals Plant Physiology, 2021 Functional redox links between lumen thiol oxidoreductase1 and serine/threonine-protein kinase STN7

2021 ◽  
Author(s):  
Jianghao Wu ◽  
Liwei Rong ◽  
Weijun Lin ◽  
Lingxi Kong ◽  
Dengjie Wei ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Disulfide Bonds ◽  
Kinase Activity ◽  
Light Harvesting ◽  
Photosynthetic Electron Transport ◽  
State Transitions ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii

Abstract In response to changing light quantity and quality, photosynthetic organisms perform state transitions, a process which optimizes photosynthetic yield and mitigates photo-damage. The serine/threonine-protein kinase STN7 phosphorylates the light-harvesting complex of photosystem II (PSII; light-harvesting complex II), which then migrates from PSII to photosystem I (PSI), thereby rebalancing the light excitation energy between the photosystems and restoring the redox poise of the photosynthetic electron transport chain. Two conserved cysteines forming intra- or intermolecular disulfide bonds in the lumenal domain (LD) of STN7 are essential for the kinase activity although it is still unknown how activation of the kinase is regulated. In this study, we show lumen thiol oxidoreductase 1 (LTO1) is co-expressed with STN7 in Arabidopsis (Arabidopsis thaliana) and interacts with the LD of STN7 in vitro and in vivo. LTO1 contains thioredoxin (TRX)-like and vitamin K epoxide reductase domains which are related to the disulfide-bond formation system in bacteria. We further show that the TRX-like domain of LTO1 is able to oxidize the conserved lumenal cysteines of STN7 in vitro. In addition, loss of LTO1 affects the kinase activity of STN7 in Arabidopsis. Based on these results, we propose that LTO1 helps to maintain STN7 in an oxidized active state in state 2 through redox interactions between the lumenal cysteines of STN7 and LTO1.

scholarly journals Peptide drugs for photopharmacology: how much of a safety advantage can be gained by photocontrol?

2020 ◽  
Vol 2 (1) ◽  
pp. FDD28 ◽  
Author(s):  
Oleg Babii ◽  
Sergii Afonin ◽  
Tim Schober ◽  
Liudmyla V Garmanchuk ◽  
Liudmyla I Ostapchenko ◽  
...  
Keyword(s):  
Chemotherapeutic Agent ◽  
In Vitro Cytotoxicity ◽  
Pharmacokinetic Parameters ◽  
Cancer Model ◽  
Pharmacokinetic Properties ◽  
Insight Into ◽  
Safety Advantage ◽  
Murine Cancer Model

Aim: To verify whether photocontrol of biological activity could augment safety of a chemotherapeutic agent. Materials & methods: LD50 values for gramicidin S and photoisomeric forms of its photoswitchable diarylethene-containing analogs were determined using mice. The results were compared with data obtained from cell viability measurements taken for the same compounds. Absorption, Distribution, Metabolism, and Elimination (ADME) tests using a murine cancer model were conducted to get insight into the underlying reasons for the observed in vivo toxicity. Results: While in vitro cytotoxicity values of the photoisomers differed substantially, the differences in the observed LD50 values were less pronounced due to unfavorable pharmacokinetic parameters. Conclusion: Despite unfavorable pharmacokinetic properties as in the representative case studied here, there is an overall advantage to be gained in the safety profile of a chemotherapeutic agent via photocontrol. Nevertheless, optimization of the pharmacokinetic parameters of photoisomers is an important issue to be addressed during the development of photopharmacological drugs.

scholarly journals Dissemination of Rat Cytomegalovirus through Infected Granulocytes and Monocytes In Vitro and In Vivo

2003 ◽  
Vol 77 (20) ◽  
pp. 11274-11278 ◽  
Author(s):  
B. W. A. van der Strate ◽  
J. L. Hillebrands ◽  
S. S. Lycklama à Nijeholt ◽  
L. Beljaars ◽  
C. A. Bruggeman ◽  
...  
Keyword(s):  
Intravenous Injection ◽  
Systemic Infection ◽  
Insight Into

ABSTRACT The role of leukocytes in the in vivo dissemination of cytomegalovirus was studied in this experiment. Rat cytomegalovirus (RCMV) could be transferred to rat granulocytes and monocytes by cocultivation with RCMV-infected fibroblasts in vitro. Intravenous injection of purified infected granulocytes or monocytes resulted in a systemic infection in rats, indicating that our model is a powerful tool to gain further insight into CMV dissemination and the development of new antivirals.

scholarly journals Poly(ADP-ribosyl)ation of p53 In Vitro and In Vivo Modulates Binding to its DNA Consensus Sequence

Neoplasia ◽  
2001 ◽  
Vol 3 (3) ◽  
pp. 179-188 ◽  
Author(s):  
Cynthia M. Simbulan-Rosenthal ◽  
Dean S. Rosenthal ◽  
RuiBai Luo ◽  
Raed Samara ◽  
Mira Jung ◽  
...  
Keyword(s):  
Consensus Sequence

scholarly journals Context effects and inefficient initiation at non-AUG codons in eucaryotic cell-free translation systems.

1989 ◽  
Vol 9 (11) ◽  
pp. 5073-5080 ◽  
Author(s):  
M Kozak
Keyword(s):  
Context Effects ◽  
Consensus Sequence ◽  
Negative Regulator ◽  
Late Event ◽  
Free Translation ◽  
Initiator Codon ◽  
Translation Systems ◽  
Short Versions

The context requirements for recognition of an initiator codon were evaluated in vitro by monitoring the relative use of two AUG codons that were strategically positioned to produce long (pre-chloramphenicol acetyl transferase [CAT]) and short versions of CAT protein. The yield of pre-CAT initiated from the 5'-proximal AUG codon increased, and synthesis of CAT from the second AUG codon decreased, as sequences flanking the first AUG codon increasingly resembled the eucaryotic consensus sequence. Thus, under prescribed conditions, the fidelity of initiation in extracts from animal as well as plant cells closely mimics what has been observed in vivo. Unexpectedly, recognition of an AUG codon in a suboptimal context was higher when the adjacent downstream sequence was capable of assuming a hairpin structure than when the downstream region was unstructured. This finding adds a new, positive dimension to regulation by mRNA secondary structure, which has been recognized previously as a negative regulator of initiation. Translation of pre-CAT from an AUG codon in a weak context was not preferentially inhibited under conditions of mRNA competition. That result is consistent with the scanning model, which predicts that recognition of the AUG codon is a late event that occurs after the competition-sensitive binding of a 40S ribosome-factor complex to the 5' end of mRNA. Initiation at non-AUG codons was evaluated in vitro and in vivo by introducing appropriate mutations in the CAT and preproinsulin genes. GUG was the most efficient of the six alternative initiator codons tested, but GUG in the optimal context for initiation functioned only 3 to 5% as efficiently as AUG. Initiation at non-AUG codons was artifactually enhanced in vitro at supraoptimal concentrations of magnesium.

scholarly journals Role for the Ran Binding Protein, Mog1p, in Saccharomyces cerevisiae SLN1-SKN7 Signal Transduction

2004 ◽  
Vol 3 (6) ◽  
pp. 1544-1556 ◽  
Author(s):  
Jade Mei-Yeh Lu ◽  
Robert J. Deschenes ◽  
Jan S. Fassler
Keyword(s):  
Signal Transduction ◽  
Transcription Factor ◽  
Osmotic Stress ◽  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Osmotic Response ◽  
Mitogen Activated Protein ◽  
Kinase Pathway

ABSTRACT Yeast Sln1p is an osmotic stress sensor with histidine kinase activity. Modulation of Sln1 kinase activity in response to changes in the osmotic environment regulates the activity of the osmotic response mitogen-activated protein kinase pathway and the activity of the Skn7p transcription factor, both important for adaptation to changing osmotic stress conditions. Many aspects of Sln1 function, such as how kinase activity is regulated to allow a rapid response to the continually changing osmotic environment, are not understood. To gain insight into Sln1p function, we conducted a two-hybrid screen to identify interactors. Mog1p, a protein that interacts with the yeast Ran1 homolog, Gsp1p, was identified in this screen. The interaction with Mog1p was characterized in vitro, and its importance was assessed in vivo. mog1 mutants exhibit defects in SLN1-SKN7 signal transduction and mislocalization of the Skn7p transcription factor. The requirement for Mog1p in normal localization of Skn7p to the nucleus does not fully account for the mog1-related defects in SLN1-SKN7 signal transduction, raising the possibility that Mog1p may play a role in Skn7 binding and activation of osmotic response genes.

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