Functions and mechanisms of non-histone protein acetylation in plants^(∞)

Lysine acetylation, an evolutionarily conserved post-translational protein modification, is reversibly catalyzed by lysine acetyltransferases and lysine deacetylases. Lysine acetylation, which was first discovered on histones, mainly functions to configure the structure of chromatin and regulate gene transcriptional activity. Over the past decade, with advances in high-resolution mass spectrometry, a vast and growing number of non-histone proteins modified by acetylation in various plant species have been identified.Lysine acetylation of non-histone proteins is widely involved in regulating biological processes in plants such as photosynthesis, energy metabolism, hormone signal transduction and stress responses. Moreover, in plants, lysine acetylation plays crucial roles in regulating enzyme activity,protein stability, protein interaction and subcellular localization. This review summarizes recent progress in our understanding of the biological functions and mechanisms of non-histone protein acetylation in plants. Research prospects in this field are also noted.

Epigenetic regulation: methylation of histone and non-histone proteins

Histone methylation is believed to play important roles in epigenetic memory in various biological processes. However, questions like whether the methylation marks themselves are faithfully transmit- ted into daughter cells and through what mechanisms are currently under active investigation. Previ- ously, methylation was considered to be irreversible, but the recent discovery of histone lysine de- methylases revealed a dynamic nature of histone methylation regulation on four of the main sites of methylation on histone H3 and H4 tails (H3K4, H3K9, H3K27 and H3K36). Even so, it is still unclear whether demethylases specific for the remaining two sites, H3K79 and H4K20, exist. Furthermore, be- sides histone proteins, the lysine methylation and demethylation also occur on non-histone proteins, which are probably subjected to similar regulation as histones. This review discusses recent pro- gresses in protein lysine methylation regulation focusing on the above topics, while referring readers to a number of recent reviews for the biochemistry and biology of these enzymes.

Mechanistic and functional extrapolation of SET and MYND domaincontaining protein 2 to pancreatic cancer

Pancreatic ductal adenocarcinoma(PDAC)is one of the most lethal neoplasms worldwide and represents the vast majority of pancreatic cancer cases.Understanding the molecular pathogenesis and the underlying mechanisms involved in the initiation,maintenance,and progression of PDAC is an urgent need,which may lead to the development of novel therapeutic strategies against this deadly cancer.Here,we review the role of SET and MYND domaincontaining protein 2(SMYD2)in initiating and maintaining PDAC development through methylating multiple tumor suppressors and oncogenic proteins.Given the broad substrate specificity of SMYD2 and its involvement in diverse oncogenic signaling pathways in many other cancers,the mechanistic extrapolation of SMYD2 from these cancers to PDAC may allow for developing new hypotheses about the mechanisms driving PDAC tumor growth and metastasis,supporting a proposition that targeting SMYD2 could be a powerful strategy for the prevention and treatment of PDAC.

Resveratrol as an epigenetic therapy for flavivirus infection:A narrative review

Flaviviruses are a group of positive-stranded RNA viruses that cause a broad spectrum of severe illnesses in humans worldwide.Clinical manifestations of flavivirus infections range from mild febrile illness to hemorrhage,shock,and neurological manifestations.Flavivirus infections cause a substantial global health impact,with an estimated more than 400 million cases of infections annually.Hence,an understanding of flavivirus-host interaction is urgently needed for new antiviral therapeutic strategies.In recent years,many aspects concerning epigenetic therapy for viral infections have been addressed,including methylation of the genome,acetylation/deacetylation of histone complex and microRNA regulation.In this context,we surveyed and reviewed the literature and summarized the epigenetic effects of resveratrol,a natural polyphenol with potential anti-viral properties,on flavivirus infections.

Arg-X Activity in Trypsin-like Complexes of the Nuclear Rroteins in the Suprastructures of Interphase Chromatin During Induction of Growth Morphogenesis Mature Germs of Wheat

The purpose of this study was to analyze spatio-temporal dynamics of localization of protease-sensitive sites Arg-X in non-histone and histone blocks of heteropolymer suprastructures （nucleoplasm, chromatin, nuclear matrix） as possible zones affecting the conformational rearrangements of the total interphase chromatin at the induction of increasing morphogenesis of mature embryos-germs of spring and transformed from its winter wheat. Germinated embryos-germs were detached from endosperm after 24 hours from the start of soaking. Cell nuclei have been allocated from embryos-germs and cleared, and then from their heteropolymer suprastructures （nucleoplasm, chromatin loosely bound with nuclear matrix and chromatin tightly bound with nuclear matrix, and nuclear matrix） were extracted by increasing ionic strength of solution. From isolated nuclear suprastructures, non-histone proteins were separated from histones using ion exchange chromatography. Trypsin-like complexes from non-histone proteins and histone blocks were isolated using the affinity chromatography. The Arg-X （tryptase） activity was assessed by cleavage of Arg-X bonds in the arginine-enriched protein protamine. Hypersensitivity to the Arg-X proteolysis in trypsin-like complexes detected at the level suprastructures of chromatin tightly bound with the nuclear matrix was shown. The most active changes of the nuclear proteome have occurred at the level of the non-histone proteins and the core histones （H2A ＋ H2B） （H3 ＋ H4） of induced to growth embryos-seedlings of winter wheat （compared to the initial spring form of wheat）. Perhaps hypersensitivity to the Arg-X activity of the trypsin-like complexes in the non-histone proteins and the core blocks of chromatin tightly bound with nuclear matrix have been entrenched during the transforming of the winter wheat from the initial spring wheat.