细菌中常见的蛋白翻译后修饰

蛋白质的翻译后修饰在生物体生命活动中发挥着重要作用,大部分蛋白质都会经历翻译后修饰。对这些修饰的了解和掌握非常重要,因为这些修饰可能会改变蛋白质的物理及化学性质,如折叠、构象、稳定性及活性,从而改变蛋白的功能。此外,修饰基团本身也可能具有某些功能。因此,分析研究蛋白质翻译后修饰具有重要意义。细菌中常见的翻译后修饰过程有糖基化、磷酸化和乙酰化,我们简要综述了这几种修饰过程。     

Application of mass spectrometry to the identification and quantification of histone post-translational modifications

The core histones are the primary protein component of chromatin, which is responsible for the packaging of eukaryotic DNA. The NH(2)-terminal tail domains of the core histones are the sites of numerous post-translational modifications that have been shown to play an important role in the regulation of chromatin structure. In this study, we discuss the recent application of modern analytical techniques to the study of histone modifications. Through the use of mass spectrometry, a large number of new sites of histone modification have been identified, many of which reside outside of the NH(2)-terminal tail domains. In addition, techniques have been developed that allow mass spectrometry to be effective for the quantitation of histone post-translational modifications. Hence, the use of mass spectrometry promises to dramatically alter our view of histone post-translational modifications.     

组蛋白翻译后修饰技术研究进展

翻译后修饰调控着真核生物大部分蛋白质的活性,这些修饰的解读对研究生物功能是必不可少的。组蛋白翻译后修饰是蛋白质翻译后修饰中研究的较好一类小分子碱性蛋白,易被各种生物大分子修饰,尤其易发生在N-末端的尾部。不同组合式修饰构成了"组蛋白密码",在细胞的发育、生长、分化和动态平衡中,组蛋白密码影响着染色体的结构状态,进而调控基因的表达状态。组蛋白翻译后修饰的研究可作为一种模式来解析蛋白质复杂的修饰状态及研究其分子功能。翻译后修饰分析技术的发展对组蛋白密码的解析是至关重要的。重点讨论组蛋白修饰分析技术的发展和应用。     

RelA/p65翻译后修饰对NF-κB转录激活的影响

RelA/p65是NF-κB的一个亚单位,其翻译后修饰能够精细地调控NF-κB的转录激活,并在炎症反应及炎症反应相关疾病的发生和发展过程中发挥重要的作用. RelA的翻译后修饰主要包括磷酸化、乙酰化、甲基化以及泛素化等.这些翻译后修饰不仅能在生理和病理的条件下有效地调控NF-κB的转录激活,彼此之间还存在着复杂的相互作用,一种翻译后修饰可以使另一种修饰增强或是抑制,从而综合而完善地调控NF κB的转录活性.本文就近年来RelA的翻译后修饰及这些修饰之间的相互作用对NF-κB信号通路影响的最新研究进展进行综述.     

Surf the post-translational modification network of p53 regulation

Among the human genome, p53 is one of the first tumor suppressor genes to be discovered. It has a wide range of functions covering cell cycle control, apoptosis, genome integrity maintenance, metabolism, fertility, cellular reprogramming and autophagy. Although different possible underlying mechanisms for p53 regulation have been proposed for decades, none of them is conclusive. While much literature focuses on the importance of individual post-translational modifications, further explorations indicate a new layer of p53 coordination through the interplay of the modifications, which builds up a complex 'network'. This review focuses on the necessity, characteristics and mechanisms of the crosstalk among post-translational modifications and its effects on the precise and selective behavior of p53.     

光敏色素A调控光响应基因表达及其翻译后修饰研究进展

光是调节植物生长发育最重要的环境信号因子之一。植物通过光受体感受自然环境中光的强度、方向以及光周期等信号的变化,从而调控其生长发育过程。光敏色素A (phytochrome A, PHYA)是植物中唯一的远红光受体蛋白,具有在黑暗下在细胞质中合成,而在照光后快速入核和降解的特性,并通过多种途径精确调节了植物光响应基因的转录网络。同时,蛋白质翻译后修饰在调节PHYA稳定性和活性的过程中发挥了重要的作用。该文论述了PHYA调节光响应基因表达以及PHYA翻译后修饰方向的研究进展,并展望了PHYA在农作物分子设计育种中的应用前景。     

Pre- and post-translational regulation of osteopontin in cancer

Osteopontin (OPN) is a matricellular protein that binds to a number of cell surface receptors including integrins and CD44. It is expressed in many tissues and secreted into body fluids including blood, milk and urine. OPN plays important physiological roles in bone remodeling, immune response and inflammation. It is also a tumour-associated protein, and elevated OPN levels are associated with tumour formation, progression and metastasis. Research has revealed a promising role for OPN as a cancer biomarker. OPN is subject to alternative splicing, as well as post-translational modifications such as phosphorylation, glycosylation and proteolytic cleavage. Functional differences have been revealed for different isoforms and post-translational modifications. The pattern of isoform expression and post-translational modification is cell-type specific and may influence the potential role of OPN in malignancy and as a cancer biomarker.     

Mass spectrometry-based strategies for characterization of histones and their post-translational modifications

Due to the intimate interactions between histones and DNA, the characterization of histones has become the focus of great attention. A series of mass spectrometry-based technologies have been dedicated to the characterization and quantitation of different histone forms. This review focuses on the discussion of mass spectrometry-based strategies used for the characterization of histones and their post-translational modifications.     

有丝分裂期间蛋白质的翻译后修饰及其功能

有丝分裂期间蛋白质的翻译后修饰对于有丝分裂顺利完成以及细胞功能发挥具有重要的调控作用。常见的修饰类型包括磷酸化修饰、糖基化修饰、SUMO化修饰、乙酰化修饰、甲基化修饰。这些翻译后修饰可以维持染色体结构、促进后期染色体分离、协助末期核膜重新形成。本文对有丝分裂过程中相关蛋白质翻译后修饰的最新类型和功能进行了系统总结,以期能为肿瘤基础研究提供新的方向。     

Post-translational modifications of ATP synthase in the heart: biology and function

The ATP synthase complex is a critical enzyme in the energetic pathways of cells because it is the enzyme complex that produces the majority of cellular ATP. It has been shown to be involved in several cardiac phenotypes including heart failure and preconditioning, a cellular protective mechanism. Understanding the regulation of this enzyme is important in understanding the mechanisms behind these important phenomena. Recently there have been several post-translational modifications (PTM) reported for various subunits of this enzyme complex, opening up the possibility of differential regulation by these PTMs. Here we discuss the known PTMs in the heart and other mammalian tissues and their implication to function and regulation of the ATP synthase.     

Applications of Genetic Code Expansion in Studying Protein Post-translational Modification

Various post-translational modifications can naturally occur on proteins, regulating the activity, subcellular localization, interaction, or stability of the proteins. However, it can be challenging to decipher the biological implication or physiological roles of site-specific modifications due to their dynamic and sub-stoichiometric nature. Genetic code expansion method, relying on an orthogonal aminoacyl-tRNA synthetase/tRNA pair, enables site-specific incorporation of non-canonical amino acids. Here we focus on the application of genetic code expansion to study site-specific protein post-translational modification in vitro and in vivo. After a brief introduction, we discuss possibilities of incorporating non-canonical amino acids containing post-translational modifications or their mimics into target proteins. This approach is applicable for Ser/Thr/Tyr phosphorylation, Tyr sulfation/nitration/hydroxylation, Lys acetylation/acylation, Lys/His mono-methylation, as well as Arg citrullination. The next section describes the use of a precursor non-canonical amino acid followed by chemical and/or enzymatic reactions to afford the desired modification, such as Cys/Lys acylation, ubiquitin and ubiquitin-like modifications, as well as Lys/Gln methylation. We also discuss means for functional regulation of enzymes involving in post-translational modifications through genetically incorporated non-canonical amino acids. Lastly, the limitations and perspectives of genetic code expansion in studying protein post-translational modification are described.     

Protein arginine methylation of non-histone proteins and its role in diseases

Protein arginine methyltransferases (PRMTs) are a family of enzymes that can methylate arginine residues on histones and other proteins. PRMTs play a crucial role in influencing various cellular functions, including cellular development and tumorigenesis. Arginine methylation by PRMTs is found on both nuclear and cytoplasmic proteins. Recently, there is increasing evidence regarding post-translational modifications of non-histone proteins by PRMTs, illustrating the previously unknown importance of PRMTs in the regulation of various cellular functions by post-translational modifications. In this review, we present the recent developments in the regulation of non-histone proteins by PRMTs.     

Post-translational modifications of apolipoprotein A-I and Po proteins in the avian peripheral nerve

Apolipoprotein A-I (apo A-I), a soluble lipid transporter, and Po, the major glycoprotein of myelin, are actively synthesized during myelination. To explore the status of post-translational modifications of these proteins in the avian PNS during rapid myelination, endoneurial slices from one day old chick sciatic nerves were incubated with various radioactive precursors that could serve as indicators of such processes. The proteins were isolated from the incubation medium (secreted fraction), the 1% Triton-X-100-soluble intracellular-endoneurial (intracellular) fraction, and myelin-related and purified compact myelin fractions by immunoprecipitation with monospecific anti-apo A-I or anti-Po antisera. Our results demonstrated that secreted apo A-I is fatty acylated, but not phosphorylated or sulfated. Avian Po protein was phosphorylated by a phorbol ester sensitive protein kinase. Sulfation, as well as fatty acylation, of avian Po protein was observed in organ culture using highly sensitive methods of detection. These results indicate that fatty acylation of secreted apo A-I and phosphorylation, sulfation and fatty acylation of Po have been conserved during evolution, and that these post-translational modifications may play a common function in various species.     

Dynorphin A(1-17) biotransformation in striatum of freely moving rats using microdialysis and matrix-assisted laser desorption/ionization mass spectrometry

The biotransformation of the opioid peptide dynorphin A(1-17) was investigated in striatum of freely moving Fischer rats, by direct infusion of this peptide, followed by recovery of the resulting biotransformation products via microdialysis and identification using matrix-assisted laser desorption/ionization mass spectrometry. The observed peptides are consistent with enzymatic cleavage at the Arg7-Ile8 position of dynorphin A(1-17), followed by terminal degradation of the resulting dynorphin A(1-7) and dynorphin A(8-17) peptides. Unexpectedly, novel post-translational modifications were found on C-terminal fragments of dynorphin A(1-17). Using tandem mass spectrometry, a covalent modification of mass 172 Da, the nature of which is not understood, was found on the tryptophan residue of C-terminal fragments (Trp14). Additional modifications, of mass 42 and 113 Da, were also found on the N-terminus (Ile8 or Pro10) of these same C-terminal fragments. The role of these modifications of C-terminal fragments has not yet been characterized.     

In vivo post-translational modifications of recombinant mussel adhesive protein in insect cells

Mussel adhesive proteins (MAPs) have been suggested as promising bioadhesives for diverse application fields, including medical uses. Previously, we successfully constructed and produced a new type of functional recombinant MAP, fp-151, in a prokaryotic Escherichia coli expression system. Even though the E. coli-derived MAP showed several excellent features, such as high production yield and efficient purification, in vitro enzymatic modification is required to convert tyrosine residues to l-3,4-dihydroxyphenyl alanine (dopa) molecules for its adhesive ability, due to the intrinsic inability of E. coli to undergo post-translational modification. In this work, we produced a soluble recombinant MAP in insect Sf9 cells, which are widely used as an effective and convenient eukaryotic expression system for eukaryotic foreign proteins. Importantly, we found that insect-derived MAP contained converted dopa residues by in vivo post-translational modification. In addition, insect-derived MAP also had other post-translational modifications including phosphorylation of serine and hydroxylation of proline that originally occurred in some natural MAPs. To our knowledge, this is the first report on in vivo post-translational modifications of MAP containing dopa and other modified amino acid residues.     

Protein lysine acylation and cysteine succination by intermediates of energy metabolism

In the past few years, several new protein post-translational modifications that use intermediates in metabolism have been discovered. These include various acyl lysine modifications (formylation, propionylation, butyrylation, crotonylation, malonylation, succinylation, myristoylation) and cysteine succination. Here, we review the discovery and the current understanding of these modifications. Several of these modifications are regulated by the deacylases, sirtuins, which use nicotinamide adenine dinucleotide (NAD), an important metabolic small molecule. Interestingly, several of these modifications in turn regulate the activity of metabolic enzymes. These new modifications reveal interesting connections between metabolism and protein post-translational modifications and raise many questions for future investigations.