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Cell Reports Oct 2023Loss of transcription-coupled histone H3 lysine 36 trimethylation (H3K36me3) contributes to shorter lifespans in eukaryotes. However, the molecular mechanism of the...
Loss of transcription-coupled histone H3 lysine 36 trimethylation (H3K36me3) contributes to shorter lifespans in eukaryotes. However, the molecular mechanism of the decline of H3K36me3 during aging remains poorly understood. Here, we report that the degradation of the methyltransferase Set2 is the cause of decreased H3K36me3 levels during chronological aging in budding yeast. We show that Set2 protein degradation during cellular senescence and chronological aging is mainly mediated by the ubiquitin-conjugating E2 enzyme Ubc3 and the E3 ligase Bre1. Lack of Bre1 or abolishment of the ubiquitination stabilizes Set2 protein, sustains H3K36me3 levels at the aging-related gene loci, and upregulates their gene expression, thus leading to extended chronological lifespan. We further illustrate that Gcn5-mediated Set2 acetylation is a prerequisite for Bre1-catalyzed Set2 polyubiquitination and proteolysis during aging. We propose that two sequential post-translational modifications regulate Set2 homeostasis, suggesting a potential strategy to target the Gcn5-Bre1-Set2 axis for intervention of longevity.
Topics: Histones; Methylation; Methyltransferases; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Ubiquitin-Conjugating Enzymes; Aging
PubMed: 37796660
DOI: 10.1016/j.celrep.2023.113186 -
Biomolecules Mar 2022Covalent binding between nitric oxide (NO) and a protein's free thiol group (SH) is termed protein S-nitrosylation. Protein S-nitrosylation is involved in cellular...
Covalent binding between nitric oxide (NO) and a protein's free thiol group (SH) is termed protein S-nitrosylation. Protein S-nitrosylation is involved in cellular regulation mechanisms that underlie a wide range of critical functions, such as apoptosis, alteration of enzyme activities, and transcription-factor stability. Impaired protein S-nitrosylation is associated with a growing list of pathophysiological conditions, such as cardiovascular disease, multiple sclerosis, pulmonary hypertension, and sickle cell disease. The enzyme paraoxonase 1 (PON1) binds to high-density lipoprotein to provide many of its antiatherogenic properties. The enzyme has a strong antioxidant capacity, which protects fats, lipids, and lipoproteins from oxidation, in addition to breaking down oxidized fats. We investigated the effect of S-S transnitrosylation on PON1 activities. Incubation of recombinant PON1 (rePON1) with nitrosylated human serum albumin (HSA-NO) resulted in S-nitrosylation of about 70% of the rePON1, as measured by Q-TOF LC/MS. S-nitrosylation significantly increased rePON1 hydrolytic activities. It also increased rePON1's ability to inhibit low-density lipoprotein oxidation induced by Cu. Finally, it increased the enzyme's penetration into macrophage cells by 31%. Our findings suggest that S-nitrosylation of rePON1 improves its biological functions which may positively affect atherosclerosis disease progression.
Topics: Antioxidants; Aryldialkylphosphatase; Humans; Lipoproteins, HDL; Lipoproteins, LDL; Protein S
PubMed: 35327606
DOI: 10.3390/biom12030414 -
Research and Practice in Thrombosis and... Mar 2023A "state of the Art" lecture titled "Hemostatic Defects in Congenital Disorders of Glycosylation" was presented at the ISTH 2022 congress. Congenital disorders of...
A "state of the Art" lecture titled "Hemostatic Defects in Congenital Disorders of Glycosylation" was presented at the ISTH 2022 congress. Congenital disorders of glycosylation (CDGs) are rare, inherited, metabolic diseases. The diagnosis of CDG is often challenging due to the broad variety of disorders, the variable level of severity, and phenotypic heterogeneity. Most CDGs are multisystem disorders, and neurologic involvement is frequent. Patients with CDG often present coagulation abnormalities characterized by low levels of procoagulant or anticoagulant factors. Antithrombin deficiency is frequently associated with factor XI deficiency and less frequently with a protein C, protein S, or factor IX deficiency. This coagulation profile differs from those observed in liver failure, disseminated intravascular coagulation, and vitamin K deficiency, and so, should prompt the physician to consider a diagnosis of CDG. Coagulopathy can lead to thrombotic and/or hemorrhagic complications. In patients with phosphomannomutase 2 deficiency (the most common CDG), thrombotic events are more frequent than hemorrhagic events. In other types of CDGs, both hemorrhagic and thrombotic events have been described. Overall, the hemostatic balance in these patients is precarious and necessitates close monitoring in a setting of acute illness with greater metabolic needs. Here, we review the most relevant hemostatic defects observed in CDG and their clinical implications. Finally, we summarize relevant new data on this topic presented at the ISTH 2022 congress.
PubMed: 37193126
DOI: 10.1016/j.rpth.2023.100142 -
Thrombosis Research Mar 2024Underlying mechanisms for bleeding and impaired thrombin generation (TG) and plasma clot formation (PCF) in patients with mild to moderate bleeding disorders (MBDs) are...
BACKGROUND
Underlying mechanisms for bleeding and impaired thrombin generation (TG) and plasma clot formation (PCF) in patients with mild to moderate bleeding disorders (MBDs) are still to be elucidated, especially in bleeding disorder of unknown cause (BDUC). The role of the natural anticoagulants activated protein C (APC) and free protein S (PS) has not yet been investigated in this patient population.
AIMS
To analyze antigen levels of APC and PS in patients with MBDs and BDUC and investigate associations to clinical bleeding phenotype and severity as well as and hemostatic capacity.
METHODS
Antigen levels of APC and free PS were measured in 262 patients from the Vienna Bleeding Biobank (VIBB), a single-center cohort study, by ELISA and compared to 61 healthy controls (HC).
RESULTS
Antigen levels of APC were higher in MBD patients than in HC when adjusted for age, sex and BMI (median (IQR) 33.1 (20.6-52.6) and 28.6 (16.4-47.2) ng/mL). This was most pronounced in patients with BDUC (35.3 (21.7-54.3) ng/mL). No differences in PS antigen levels between patients and HC were seen overall, or according to specific diagnoses. Further, no association between APC or PS and bleeding severity or global tests of hemostasis or TG were identified, while paradoxically APC weakly correlated with shorter lag time and time to peak of PCF in BDUC.
CONCLUSION
Our data demonstrate increased antigen levels of APC in BDUC, which might contribute to the bleeding tendency in some patients and could be a future therapeutic target in BDUC.
Topics: Humans; Protein C; Cohort Studies; Blood Coagulation Disorders; Anticoagulants; Enzyme-Linked Immunosorbent Assay
PubMed: 38324941
DOI: 10.1016/j.thromres.2024.01.018 -
Open Biology Apr 2022Protein S-acylation, more commonly known as protein palmitoylation, is a biological process defined by the covalent attachment of long chain fatty acids onto cysteine... (Review)
Review
Protein S-acylation, more commonly known as protein palmitoylation, is a biological process defined by the covalent attachment of long chain fatty acids onto cysteine residues of a protein, effectively altering the local hydrophobicity and influencing its stability, localization and overall function. Observed ubiquitously in all eukaryotes, this post translational modification is mediated by the 23-member family of zDHHC protein acyltransferases in mammals. There are thousands of proteins that are S-acylated and multiple zDHHC enzymes can potentially act on a single substrate. Since its discovery, numerous methods have been developed for the identification of zDHHC substrates and the individual members of the family that catalyse their acylation. Despite these recent advances in assay development, there is a persistent gap in knowledge relating to zDHHC substrate specificity and recognition, that can only be thoroughly addressed through reconstitution. Herein, we will review the various methods currently available for reconstitution of protein S-acylation for the purposes of identifying enzyme-substrate pairs with a particular emphasis on the advantages and disadvantages of each approach.
Topics: Acetyltransferases; Acylation; Animals; Mammals; Protein Processing, Post-Translational; Protein S; Substrate Specificity
PubMed: 35414257
DOI: 10.1098/rsob.210390 -
Biophysical Journal Oct 2020Bcl-xL is a major inhibitor of apoptosis, a fundamental homeostatic process of programmed cell death that is highly conserved across evolution. Because it plays...
Bcl-xL is a major inhibitor of apoptosis, a fundamental homeostatic process of programmed cell death that is highly conserved across evolution. Because it plays prominent roles in cancer, Bcl-xL is a major target for anticancer therapy and for studies aimed at understanding its structure and activity. Although Bcl-xL is active primarily at intracellular membranes, most studies have focused on soluble forms of the protein lacking both the membrane-anchoring C-terminal tail and the intrinsically disordered loop, and this has resulted in a fragmented view of the protein's biological activity. Here, we describe the conformation of full-length Bcl-xL. Using NMR spectroscopy, molecular dynamics simulations, and isothermal titration calorimetry, we show how the three structural elements affect the protein's structure, dynamics, and ligand-binding activity in both its soluble and membrane-anchored states. The combined data provide information about the molecular basis for the protein's functionality and a view of its complex molecular mechanisms.
Topics: Apoptosis; Magnetic Resonance Spectroscopy; Molecular Dynamics Simulation; Protein Conformation; bcl-X Protein
PubMed: 32888404
DOI: 10.1016/j.bpj.2020.08.014 -
Cureus Oct 2023Protein S is a glycoprotein created by the body that aids in the prevention of a hypercoagulable state. Protein S-deficient patients are placed on anticoagulant...
Protein S is a glycoprotein created by the body that aids in the prevention of a hypercoagulable state. Protein S-deficient patients are placed on anticoagulant regimens, as there is no current definitive cure. Failure to bring balance to the hematological system in these patients will lead to complications such as widespread clot formation and pulmonary embolisms. Here, we present a 74-year-old female who was admitted to the ICU after collapsing. She presented with respiratory failure, urinary tract infection (UTI), and pneumonia. Magnetic resonance imaging (MRI) scans depicted a thrombus in the distal right transverse sinus and sigmoid sinus. Her hematologic workup showed normal levels of homocysteine, fibrinogen, and protein C levels but protein S levels were reduced to 24%. This case displays the intricate presentation of a rare hematological disease as well as the importance of routine follow-up to maintain patient health.
PubMed: 37954832
DOI: 10.7759/cureus.46864 -
Cells Dec 2022It has been four decades since protein S-glutathionylation was proposed to serve as a regulator of cell metabolism. Since then, this redox-sensitive covalent... (Review)
Review
BACKGROUND
It has been four decades since protein S-glutathionylation was proposed to serve as a regulator of cell metabolism. Since then, this redox-sensitive covalent modification has been identified as a cell-wide signaling platform required for embryonic development and regulation of many physiological functions.
SCOPE OF THE REVIEW
Mitochondria use hydrogen peroxide (HO) as a second messenger, but its availability must be controlled to prevent oxidative distress and promote changes in cell behavior in response to stimuli. Experimental data favor the function of protein S-glutathionylation as a feedback loop for the inhibition of mitochondrial HO production.
MAJOR CONCLUSIONS
The glutathione pool redox state is linked to the availability of HO, making glutathionylation an ideal mechanism for preventing oxidative distress whilst playing a part in desensitizing mitochondrial redox signals.
GENERAL SIGNIFICANCE
The biological significance of glutathionylation is rooted in redox status communication. The present review critically evaluates the experimental evidence supporting its role in negating mitochondrial HO production for cell signaling and prevention of electrophilic stress.
Topics: Hydrogen Peroxide; Protein S; Mitochondria; Glutathione; Oxidation-Reduction
PubMed: 36611901
DOI: 10.3390/cells12010107 -
Thrombosis Research Mar 2023COVID-19 is associated with an increased thromboembolic risk. However, the mechanisms triggering clot formation in those patients remain unknown.
INTRODUCTION
COVID-19 is associated with an increased thromboembolic risk. However, the mechanisms triggering clot formation in those patients remain unknown.
PATIENTS AND METHODS
In 118 adult Caucasian severe but non-critically ill COVID-19 patients (median age 58 years; 73 % men) and 46 controls, we analyzed in vitro plasma thrombin generation profile (calibrated automated thrombogram [CAT assay]) and investigated thrombophilia-related factors, such as protein C and antithrombin activity, free protein S level, presence of antiphospholipid antibodies and factor V Leiden R506Q and prothrombin G20210A mutations. We also measured circulating von Willebrand factor (vWF) antigen and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) antigen and activity. In patients, blood samples were collected on admission to the hospital before starting any therapy, including heparin. Finally, we examined the relationship between observed alterations and disease follow-up, such as thromboembolic complications.
RESULTS
COVID-19 patients showed 17 % lower protein C activity, 22 % decreased free protein S levels, and a higher prevalence of positive results for IgM anticardiolipin antibodies. They also had 151 % increased vWF, and 27 % decreased ADAMTS13 antigens compared with controls (p < 0.001, all). On the contrary, thrombin generation potential was similar to controls. In the follow-up, pulmonary embolism (PE) occurred in thirteen (11 %) patients. They were characterized by a 55 % elevated D-dimer (p = 0.04) and 2.7-fold higher troponin I (p = 0.002) during hospitalization and 29 % shorter time to thrombin peak in CAT assay (p = 0.009) compared to patients without PE.
CONCLUSIONS
In COVID-19, we documented prothrombotic abnormalities of peripheral blood. PE was characterized by more dynamic thrombin generation growth in CAT assay performed on admittance to the hospital.
Topics: Humans; ADAMTS13 Protein; COVID-19; Protein C; Thrombin; von Willebrand Factor; Protein S
PubMed: 36709678
DOI: 10.1016/j.thromres.2023.01.016 -
Life Science Alliance Apr 2023Posttranslational protein S-palmitoylation regulates the localization and function of its target proteins involved in diverse cellular processes including meiosis. In...
Posttranslational protein S-palmitoylation regulates the localization and function of its target proteins involved in diverse cellular processes including meiosis. In this study, we demonstrate that S-palmitoylation mediated by Erf2-Erf4 and Akr1 palmitoylacyltransferases is required at multiple meiotic stages in the fission yeast We find that S-palmitoylation by Erf2-Erf4 is required for Ras1 localization at the cell periphery to enrich at the cell conjugation site for mating pheromone response. In the absence of Erf2 or Erf4, mutant cells are sterile. A role of Akr1 S-palmitoylating the nuclear fusion protein Tht1 to function in karyogamy is identified. We demonstrate that S-palmitoylation stabilizes and localizes Tht1 to ER, interacting with Sey1 ER fusion GTPase for proper meiotic nuclear fusion. In , , or mutant, meiotic cells, haploid nuclei are unfused with subsequent chromosome segregation defects. Erf2-Erf4 has an additional substrate of the spore coat protein Isp3. In the absence of Erf2, Isp3 is mislocalized from the spore coat. Together, these results highlight the versatility of the cellular processes in which protein S-palmitoylation participates.
Topics: Lipoylation; Meiosis; Schizosaccharomyces; Schizosaccharomyces pombe Proteins
PubMed: 36650056
DOI: 10.26508/lsa.202201755