14-3-3蛋白家族及其临床应用研究进展

14-3-3蛋白家族是一组高度保守的可溶性酸性蛋白质,分子量在28～33kD之间,广泛分布于各种真核生物之中。该蛋白能够特异地结合含有磷酸化丝氨酸或苏氨酸的肽段,参与多种信号转导途径。14-3-3蛋白调节着许多重要细胞生命活动,如：新陈代谢、细胞周期、细胞生长发育、细胞的存活和凋亡以及基因转录,该蛋白家族异常与疾病的发生密切相关,尤其是14-3-3蛋白在脑脊液中的分布与一些神经系统疾病密切相关。14-3-3蛋白已成为一些疾病的临床诊断指标,其作为疾病治疗的靶点也在研究之中。主要阐述了14-3-3蛋白的结构、功能、及其在疾病治疗中的应用。     

14-3-3:保护性信号转导调节蛋白

14 3 3蛋白家族是真核细胞中高度保守的可溶性蛋白。在哺乳动物 ,14 3 3蛋白主要存在于脑。 14 3 3蛋白与许多蛋白结合 ,在细胞凋亡、生长、增殖的信号转导过程中发挥关键的调节作用 ,是细胞内重要的保护性蛋白。 14 3 3蛋白还是一些脑疾病的诊断标志。 14 3 3蛋白有可能成为治疗一些疾病的靶点     

14-3-3蛋白研究进展

14-3-3蛋白是高度保守的、所有真核生物细胞中都普遍存在的、在大多数生物物种中由一个基因家族编码的一类蛋白调控家族。它几乎参与生命体所有的生理反应过程,人们在各种组织细胞中发现了各种不同的14-3-3蛋白。作为与磷酸丝氨酸／苏氨酸结合的第一信号分子,14-3-3蛋白在细胞的信号转导中起着至关重要的作用,尤其是它直接参与调节蛋白激酶和蛋白磷酸化酶的活性,被称为蛋白质与蛋白质相互作用的”桥梁蛋白”;它可以与转录因子结合形成复合体,调节相关基因的表达。一些研究表明,14-3-3蛋白调控机制的紊乱可以直接导致疾病的发生,在临床上14-3-3蛋白常常可以作为诊断的标志物。     

朊蛋白与信号蛋白14-3-3β的相互作用研究

为进一步确定PrP蛋白与14-3-3蛋白是否发生分子间的相互作用并确定PrP蛋白与14-3-3蛋白相互作用的区域,利用免疫共沉淀、pull down和能量共振转移(FRET)实验检测PrP蛋白与人14-3-3蛋白是否发生分子间的相互作用及相互作用的部位。结果证明,PrP蛋白与人14-3-3蛋白在体外、组织水平及细胞水平均可以发生相互作用,且证实作用的部位在PrP蛋白的106-126位氨基酸。该结果为进一步研究14-3-3蛋白在Prion疾病中的影响及Prion疾病的发病机制奠定了一定基础。     

14-3-3蛋白和神经退行性疾病

14-3-3蛋白以二聚体形式存在,识别磷酸丝氨酸／苏氨酸连接的信号分子,通过与其配体蛋白质相互作用,参与细胞信号转导、细胞周期调控和细胞问运输。14-3-3蛋自在脑组织中含量丰富,所有神经元、星形胶质细胞、少突肢质细胞、小胶质细胞的胞液与胞核中都有表述。14-3-3蛋白与神经退行性疾病阿尔茨海默病和帕金森病的发生过程关系密切。     

人14-3-3蛋白家族的生物信息学分析

目的:分析人14-3-3蛋白家族的同源性及分子进化关系。方法:利用已公布的人基因组数据库,采用BLASTN程序检索人14-3-3蛋白家族各成员的编码基因和假基因,并利用DNAMAN软件进行序列联配,绘制其分子进化树。结果:该家族半数成员具有多个假基因序列,为返转座类型假基因。进化分析表明该家族有共同的祖先,可归为3个亚类。结论:人14-3-3蛋白家族每个成员长期进化所形成的多样性提示其功能具有独特性。     

土生隐球酵母14-3-3蛋白耐铝能力的研究

14-3-3蛋白家族是由多个高度保守的成员构成的调节性蛋白质家族,它们主要以磷酸化的形式与伴侣蛋白相互作用,并能够以多种方式来影响靶蛋白。通过构建14-3-3蛋白原核表达载体,纯化重组蛋白获得14-3-3蛋白抗体。为了验证14-3-3蛋白基因在耐铝中的作用,构建14-3-3酵母表达载体,得到14-3-3过表达酵母菌株。在5mmol/L铝浓度下,转基因酵母比对照酵母长势好,这表明14-3-3蛋白通过促进生长赋予酵母对铝胁迫的耐受性。     

14-3-3蛋白参与植物应答非生物胁迫的研究进展

14-3-3蛋白是一种在真核生物细胞中普遍存在且高度保守的蛋白。该蛋白在大多数物种中由一个基因家族编码,并以同源或异源二聚体的形式存在。不同的14-3-3蛋白同工型具有不同的细胞特异性,可通过识别特异的磷酸化或非磷酸化序列与靶蛋白相互作用。14-3-3蛋白在植物生长和发育的各个方面都起重要作用。本文主要围绕植物14-3-3蛋白的种类、结构、磷酸化或非磷酸化识别序列及其响应干旱、冷冻、盐碱、营养和机械胁迫等的分子机制研究进展进行综述。     

14-3-3蛋白对植物发育的调控作用

14-3-3蛋白是高度保守并在真核生物中普遍存在的一类调节蛋白。不同的14-3-3蛋白同工型具有不同的细胞特异性, 并通过识别特异的磷酸化序列与靶蛋白相互作用, 被称为蛋白质与蛋白质相互作用的桥梁蛋白。在植物生长发育过程中, 14-3-3蛋白通过与其它蛋白的相互作用参与多种植物激素信号转导、各种代谢调控、物质运输和光信号应答等调控过程。该文主要对近年来有关14-3-3蛋白在植物生长发育中的调控作用, 特别是14-3-3蛋白参与调控植物激素信号转导等方面的研究进展进行综述。     

植物中14-3-3蛋白的主要功能

14-3-3蛋白家族广泛存在于真核生物中,序列高度保守。主要以同源或异源二聚体形式存在,可以同时与两个靶蛋白或者与一个靶蛋白的两个结构域相互作用,通过与靶蛋白上的一小段共有序列的磷酸化丝氨酸/苏氨酸残基结合来发挥其调控功能。本文综述了植物中的14-3-3蛋白及其主要功能,并重点综述了14-3-3蛋白对植物基本碳、氮代谢的调控。     

14-3-3 proteins as potential therapeutic targets

The 14-3-3 family of phosphoserine/phosphothreonine-binding proteins dynamically regulates the activity of client proteins in various signaling pathways that control diverse physiological and pathological processes. In response to environmental cues, 14-3-3 proteins orchestrate the highly regulated flow of signals through complex networks of molecular interactions to achieve well-controlled physiological outputs, such as cell proliferation or differentiation. Accumulating evidence now supports the concept that either an abnormal state of 14-3-3 protein expression, or dysregulation of 14-3-3/client protein interactions, contributes to the development of a large number of human diseases. In particular, clinical investigations in the field of oncology have demonstrated a correlation between upregulated 14-3-3 levels and poor survival of cancer patients. These studies highlight the rapid emergence of 14-3-3 proteins as a novel class of molecular target for potential therapeutic intervention. The current status of 14-3-3 modulator discovery is discussed.     

Purification, Properties, and Immunohistochemical Localisation of Human Brain 14-3-3 Protein

Abstract: A protein has been purified from human brain that appears to be the human equivalent of bovine 14-3-3 protein. On polyacrylamide gel electrophoresis the protein migrates as a faster major component, termed 14-3-3-2 protein, and a slower minor component, termed 14-3-3-1 protein, which consists of approximately 12% of the total protein. Both 14-3-3-1 and 14-3-3-2 have a native molecular weight of approximately 67,000. 14-3-3-2 appears to have the subunit composition (αβ; 14-3-3-1 has the composition ββ. Peptide mapping with Stuphvlococcus aureus V8 proteinase shows that α and β subunits are unrelated but the β and β' subunits show some common peptides. Immunoperoxidase labelling shows that 14-3-3 is localised in neurones in the human cerebral cortex. 14-3-3 shows no enolase, creatine kinase, triose phosphate isomerase, ATPase, cyclic nucleotide-dependent protein kinase, or purine nucleoside phosphorylase activity. 14-3-3 does not bind calcium and does not appear to be related to calmodulin, calcineurin, tubulin, neurofilament proteins, clathrin-associated proteins, or tropomyosin. The functional significance of this neuronal protein remains obscure.     

14-3-3 proteins in neurological disorders

14-3-3 proteins were originally discovered as a family of proteins that are highly expressed in the brain. Through interactions with a multitude of binding partners, 14-3-3 proteins impact many aspects of brain function including neural signaling, neuronal development and neuroprotection. Although much remains to be learned and understood, 14-3-3 proteins have been implicated in a variety of neurological disorders based on evidence from both clinical and laboratory studies. Here we will review previous and more recent research that has helped us understand the roles of 14-3-3 proteins in both neurodegenerative and neuropsychiatric diseases.     

Deciphering the role of 14-3-3 proteins

14-3-3 Proteins are found to bind to a growing number of eukaryotic proteins and evidence is accumulating that 14-3-3 proteins serve as modulators of enzyme activity. Several 14-3-3 protein recognition motifs have been identified and an increasing number of target proteins have been found to contain more than one binding site for a 14-3-3 protein. It is thus possible that 14-3-3 dimers function as clamps that simultaneously bind to two motifs within a single binding partner. Phosphorylation of a number of binding motifs has been shown to increase the affinity for 14-3-3 proteins but other mechanisms also regulate the association. It has recently been demonstrated that fusicoccin induces a tight association between 14-3-3 proteins and the plant plasma membrane H⁺-ATPase. Phorbol esters and other hydrophobic molecules may have a similar effect on the association between 14-3-3 proteins and specific binding partners.     

The role of 14-3-3 proteins in cell signalling pathways and virus infection

14-3-3 proteins are highly conserved in species ranging from yeast to mammals and regulate numerous signalling pathways via direct interactions with proteins carrying phosphorylated 14-3-3–binding motifs. Recent studies have shown that 14-3-3 proteins can also play a role in viral infections. This review summarizes the biological functions of 14-3-3 proteins in protein trafficking, cell-cycle control, apoptosis, autophagy and other cell signal transduction pathways, as well as the associated mechanisms. Recent findings regarding the role of 14-3-3 proteins in viral infection and innate immunity are also reviewed.     

14-3-3 proteins are involved in the regulation of mammalian cell proliferation

Summary. The 14-3-3 proteins are a family of abundant, widely expressed acidic polypeptides. The seven isoforms interact with over 70 different proteins. 14-3-3 isoforms have been demonstrated to be involved in the control of positive as well as negative regulators of mammalian cell proliferation. Here we used the approach of inactivating 14-3-3 protein functions via overexpression of dominant negative mutants to analyse the role of 14-3-3 proteins in mammalian cell proliferation. We found 14-3-3 dominant negative mutants to downregulate the proliferation rates of HeLa cells. Overexpression of these dominant negative mutants triggers upregulation of the protein levels of the cyclin-dependent kinase inhibitor p27, a major negative cell cycle regulator. In addition, they downregulate the protein levels of the important cell cycle promoter cyclin D1. These data provide new insights into mammalian cell proliferation control and allow a better understanding of the functions of 14-3-3 proteins.     

The cyclin-dependent kinase 11 interacts with 14-3-3 proteins

Cyclin-dependent kinase 11 isoforms (CDK11) are members of the p34(cdc2) superfamily. They have been shown to play a role in RNA processing and apoptosis. In the present study, we investigate whether CDK11 interacts with 14-3-3 proteins. Our study shows that the putative 14-3-3 binding site (113-RHRSHS-118) within the N-terminal domain of CDK11(p110) is functional. Endogenous CDK11(p110) binds directly to 14-3-3 proteins and phosphorylation of the serine 118 within the RHRSHS motif seems to be required for the binding. Besides, CDK11(p110) is capable of interacting with several different isoforms of 14-3-3 proteins both in vitro and in vivo. The interaction of 14-3-3 gamma with CDK11(p110) occurs throughout the entire cell cycle and reaches maximum at the G2/M phase. Interestingly, 14-3-3 gamma shows strong interaction with N-terminal portion of caspase-cleaved CDK11(p110) (CDK11(p60)) product at 48 h after Fas treatment, which correlates with the maximal cleavage level of CDK11(p110) and the maximum activation level of CDK11 kinase activity during apoptosis. Collectively, these results suggest that CDK11 kinases could be regulated by interaction with 14-3-3 proteins during cell cycle and apoptosis.