BACKGROUND: Obesity is a major health burden. Preadipocytes proliferate and differentiate in mature adipocytes in the adipogenic process, which could be a potential therapeutic approach for obesity. Deficiency of SIRT6, a stress-responsive protein deacetylase and mono-ADP ribosyltransferase enzyme, blocks adipogenesis. Mutants of SIRT6 (N308K/A313S) were recently linked to the in the long lifespan Ashkenazi Jews. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect adipogenesis at the transcriptional and epigenetic level. METHODS: We analyzed the role of SIRT6 wild-type (WT) or SIRT6 centenarian-associated mutant (N308K/A313S) overexpression in adipogenesis, by creating stably transduced preadipocyte cell lines using lentivirus on the 3T3-L1 model. Histone post-translational modifications (PTM: acetylation, methylation) and transcriptomic changes were analyzed by mass spectrometry (LC-MS/MS) and RNA-Seq, respectively, in 3T3-L1 adipocytes. In addition, the adipogenic process and related signaling pathways were investigated by bioinformatics and biochemical approaches. RESULTS: Overexpression of centenarian-associated SIRT6 mutant increased adipogenic differentiation to a similar extent compared to the WT form. However, it triggered distinct histone PTM profiles in mature adipocytes, with significantly higher acetylation levels, and activated divergent transcriptional programs, including those dependent on signaling related to the sympathetic innervation and to PI3K pathway. 3T3-L1 mature adipocytes overexpressing SIRT6 N308K/A313S displayed increased insulin sensitivity in a neuropeptide Y (NPY)-dependent manner. CONCLUSIONS: SIRT6 N308K/A313S overexpression in mature adipocytes ameliorated glucose sensitivity and impacted sympathetic innervation signaling. These findings highlight the importance of targeting SIRT6 enzymatic activities to regulate the co-morbidities associated with obesity.
- MeSH
- Adipogenesis * genetics MeSH
- 3T3-L1 Cells * MeSH
- Epigenesis, Genetic * genetics MeSH
- Histones metabolism genetics MeSH
- Humans MeSH
- Mutation MeSH
- Mice MeSH
- Obesity genetics metabolism MeSH
- Protein Processing, Post-Translational genetics MeSH
- Sirtuins * genetics metabolism MeSH
- Adipocytes * metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Aging is the most critical factor that influences the quality of post-ovulatory oocytes. Age-related molecular pathways remain poorly understood in fish oocytes. In this study, we examined the effect of oocyte aging on specific histone acetylation in common carp Cyprinus carpio. The capacity to progress to the larval stage in oocytes that were aged for 28 h in vivo and in vitro was evaluated. Global histone modifications and specific histone acetylation (H3K9ac, H3K14ac, H4K5ac, H4K8ac, H4K12ac, and H4K16ac) were investigated during oocyte aging. Furthermore, the activity of histone acetyltransferase (HAT) was assessed in fresh and aged oocytes. Global histone modifications did not exhibit significant alterations during 8 h of oocyte aging. Among the selected modifications, H4K12ac increased significantly at 28 h post-stripping (HPS). Although not significantly different, HAT activity exhibited an upward trend during oocyte aging. Results of our current study indicate that aging of common carp oocytes for 12 h results in complete loss of egg viability rates without any consequence in global and specific histone modifications. However, aging oocytes for 28 h led to increased H4K12ac. Thus, histone acetylation modification as a crucial epigenetic mediator may be associated with age-related defects, particularly in oocytes of a more advanced age.
- MeSH
- Acetylation MeSH
- Histone Acetyltransferases genetics MeSH
- Histones genetics MeSH
- Carps genetics growth & development MeSH
- Oocytes growth & development metabolism MeSH
- Protein Processing, Post-Translational genetics MeSH
- Aging genetics MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
The p53 and Mouse double minute 2 (MDM2) proteins are hubs in extensive networks of interactions with multiple partners and functions. Intrinsically disordered regions help to adopt function-specific structural conformations in response to ligand binding and post-translational modifications. Different techniques have been used to dissect interactions of the p53-MDM2 pathway, in vitro, in vivo, and in situ each having its own advantages and disadvantages. This review uses the p53-MDM2 to show how different techniques can be employed, illustrating how a combination of in vitro and in vivo techniques is highly recommended to study the spatio-temporal location and dynamics of interactions, and to address their regulation mechanisms and functions. By using well-established techniques in combination with more recent advances, it is possible to rapidly decipher complex mechanisms, such as the p53 regulatory pathway, and to demonstrate how protein and nucleotide ligands in combination with post-translational modifications, result in inter-allosteric and intra-allosteric interactions that govern the activity of the protein complexes and their specific roles in oncogenesis. This promotes elegant therapeutic strategies that exploit protein dynamics to target specific interactions.
- MeSH
- Phosphorylation genetics MeSH
- Nuclear Proteins MeSH
- Humans MeSH
- Mice MeSH
- Tumor Suppressor Protein p53 genetics MeSH
- DNA Damage genetics MeSH
- Protein Processing, Post-Translational genetics MeSH
- Cell Cycle Proteins genetics MeSH
- Proto-Oncogene Proteins c-mdm2 genetics MeSH
- Protein Binding genetics MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Hepatitis B virus (HBV) core protein (HBc) plays many roles in the HBV life cycle, such as regulation of transcription, RNA encapsidation, reverse transcription, and viral release. To accomplish these functions, HBc interacts with many host proteins and undergoes different post-translational modifications (PTMs). One of the most common PTMs is ubiquitination, which was shown to change the function, stability, and intracellular localization of different viral proteins, but the role of HBc ubiquitination in the HBV life cycle remains unknown. Here, we found that HBc protein is post-translationally modified through K29-linked ubiquitination. We performed a series of co-immunoprecipitation experiments with wild-type HBc, lysine to arginine HBc mutants and wild-type ubiquitin, single lysine to arginine ubiquitin mutants, or single ubiquitin-accepting lysine constructs. We observed that HBc protein could be modified by ubiquitination in transfected as well as infected hepatoma cells. In addition, ubiquitination predominantly occurred on HBc lysine 7 and the preferred ubiquitin chain linkage was through ubiquitin-K29. Mass spectrometry (MS) analyses detected ubiquitin protein ligase E3 component N-recognin 5 (UBR5) as a potential E3 ubiquitin ligase involved in K29-linked ubiquitination. These findings emphasize that ubiquitination of HBc may play an important role in HBV life cycle.
- MeSH
- Arginine genetics MeSH
- Cell Line MeSH
- Hep G2 Cells MeSH
- HEK293 Cells MeSH
- Hepatitis B genetics MeSH
- Carcinoma, Hepatocellular genetics MeSH
- Humans MeSH
- Lysine genetics MeSH
- Cell Line, Tumor MeSH
- Protein Processing, Post-Translational genetics MeSH
- Ubiquitin genetics MeSH
- Ubiquitination genetics MeSH
- Ubiquitin-Protein Ligases genetics MeSH
- Viral Proteins genetics MeSH
- Hepatitis B virus genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- MeSH
- Gene Expression genetics MeSH
- Carcinogenesis genetics immunology drug effects MeSH
- Humans MeSH
- Protein Processing, Post-Translational genetics immunology drug effects MeSH
- Cell Proliferation genetics drug effects MeSH
- Sumoylation genetics immunology MeSH
- Ubiquitination * genetics immunology drug effects MeSH
- Check Tag
- Humans MeSH
We examined the levels and distribution of post-translationally modified histones and protamines in human sperm. Using western blot immunoassay, immunofluorescence, mass spectrometry (MS), and FLIM-FRET approaches, we analyzed the status of histone modifications and the protamine P2. Among individual samples, we observed variability in the levels of H3K9me1, H3K9me2, H3K27me3, H3K36me3, and H3K79me1, but the level of acetylated (ac) histones H4 was relatively stable in the sperm head fractions, as demonstrated by western blot analysis. Sperm heads with lower levels of P2 exhibited lower levels of H3K9ac, H3K9me1, H3K27me3, H3K36me3, and H3K79me1. A very strong correlation was observed between the levels of P2 and H3K9me2. FLIM-FRET analysis additionally revealed that acetylated histones H4 are not only parts of sperm chromatin but also appear in a non-integrated form. Intriguingly, H4ac and H3K27me3 were detected in sperm tail fractions via western blot analysis. An appearance of specific histone H3 and H4 acetylation and H3 methylation in sperm tail fractions was also confirmed by both LC-MS/MS and MALDI-TOF MS analysis. Taken together, these data indicate that particular post-translational modifications of histones are uniquely distributed in human sperm, and this distribution varies among individuals and among the sperm of a single individual.
- MeSH
- Acetylation MeSH
- Chromatin genetics MeSH
- Histone-Lysine N-Methyltransferase biosynthesis genetics MeSH
- Histones genetics metabolism MeSH
- Humans MeSH
- Methylation MeSH
- Protein Processing, Post-Translational genetics MeSH
- Amino Acid Sequence MeSH
- Spermatozoa growth & development metabolism MeSH
- Tandem Mass Spectrometry MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The metazoan Sec61 translocon transports polypeptides into and across the membrane of the endoplasmic reticulum via two major routes, a well-established co-translational pathway and a post-translational alternative. We have used two model substrates to explore the elements of a secretory protein precursor that preferentially direct it towards a co- or post-translational pathway for ER translocation. Having first determined the capacity of precursors to enter ER derived microsomes post-translationally, we then exploited semi-permeabilized mammalian cells specifically depleted of key membrane components using siRNA to address their contribution to the membrane translocation process. These studies suggest precursor chain length is a key factor in the post-translational translocation at the mammalian ER, and identify Sec62 and Sec63 as important components acting on this route. This role for Sec62 and Sec63 is independent of the signal sequence that delivers the precursor to the ER. However, the signal sequence can influence the subsequent membrane translocation process, conferring sensitivity to a small molecule inhibitor and dictating reliance on the molecular chaperone BiP. Our data support a model where secretory protein precursors that fail to engage the signal recognition particle, for example because they are short, are delivered to the ER membrane via a distinct route that is dependent upon both Sec62 and Sec63. Although this requirement for Sec62 and Sec63 is unaffected by the specific signal sequence that delivers a precursor to the ER, this region can influence subsequent events, including both Sec61 mediated transport and the importance of BiP for membrane translocation. Taken together, our data suggest that an ER signal sequence can regulate specific aspects of Sec61 mediated membrane translocation at a stage following Sec62/Sec63 dependent ER delivery.
Glukokortikoidy jsou protizánětlivá léčiva, která ovlivňují expresi genů, transkripci v jádře, posttranskripční a posttranslační mechanismy v cytoplazmě. Aktivita prozánětlivých proteinů je regulována i posttranskripčními mechanismy, které ovlivňují stabilitu mRNA. Pochopení nových signálních drah regulujících protizánětlivou aktivitu glukokortikoidů je cestou k dosažení maximální léčebné odpovědi v organismu.
Glucocorticoids are anti-inflammatory drugs that regulate gene expression, nuclear transcription and post-transcriptional and post-translational mechanisms in the cytoplasm. The activity of the anti-inflammatory proteins is also regulated by the post-transcriptional mechanisms that control mRNA stability. Understanding new signalling pathways involved in the regulation of anti-inflammatory activity of glucocorticoids is prerequisite for achieving the best possible therapeutic response.
- MeSH
- Glucocorticoids pharmacokinetics pharmacology MeSH
- Histones immunology metabolism drug effects MeSH
- RNA Processing, Post-Transcriptional genetics immunology drug effects MeSH
- Protein Processing, Post-Translational genetics drug effects MeSH
- Gene Expression Regulation genetics immunology drug effects MeSH
- Inflammation drug therapy genetics immunology MeSH
