人前列腺癌PC-3细胞膜蛋白组学的分析

目的分析人前列腺癌PC-3细胞中的所有膜蛋白,全面展示PC-3细胞中的蛋白质表达谱。方法采用一维SDS-PAGE,结合高效液相色谱-串联质谱的方法,分离并鉴定PC-3细胞中的膜蛋白。结果在严格的过滤参数条件下,PC-3细胞中鉴定出2172种蛋白,其中1499种经过基因本体评注(GOA)显示为已知细胞组分,其余为未知细胞组分。在已知细胞组分中,564种(37.6%)蛋白为质膜蛋白,其中138种为跨膜蛋白。跨膜蛋白中,21.17%被预测至少有1个跨膜区,57.66%有1～3个跨膜区,30.66%有4～9个跨膜区,11.66%有不少于10个跨膜区。许多新的蛋白也被鉴定,其中包括假设蛋白和一些cD-NA序列。结论这些被鉴定蛋白的生物学功能和理化性质将有助于进一步理解前列腺癌侵袭和转移的分子机制,为寻找与前列腺癌转移相关的分子提供新的实验证据。     

Evaluation of the extracellular proteins in full-scale activated sludges

The proteins present in the extracellular polymeric substances (EPS) of activated sludge flocs were investigated using three cation-associated extraction methods. The subproteomes generated from four full-scale activated sludges were subsequently fractionated by ammonium sulfate precipitation and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that each extraction method led to unique SDS-PAGE protein profiles, which provided strong evidence that the extracted proteins are uniquely associated with specific cations in activated sludge flocs. The comparison of protein profiles across sludges from different treatment plants revealed that extracts obtained using a cation-exchange resin exhibited similar protein banding patterns while sulfide- and base-extracted EPS led to more variable protein profiles. Analysis of several SDS-PAGE bands by liquid chromatography-tandem mass spectrometry of tryptic digests led to the identification of several bacterial proteins as well as sewage-derived polypeptides (human elastase IIIA and keratins). Their putative roles in activated sludges and their association with targeted cations are proposed.     

Glutathione improves the cold resistance of Lactobacillus sanfranciscensis by physiological regulation

The microenvironmental manipulation of glutathione (GSH) on improving cold resistance of Lactobacillus sanfranciscensis DSM 20451^T was investigated in this study. It was proved that GSH relieves the metabolic disorder of cells under cold stress, and prevents the decreased activities of related key enzymes such as pyruvate kinase (PK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase (LDH) upon cold challenges. Higher intracellular ATP level was also found in cells with GSH under cold stress. Moreover, cells with imported GSH had significantly higher intracellular than the control during cold treatment. In addition, proteomics analysis showed more exciting findings that the protective function of GSH under cold stress was related to metabolic regulation and the multi-control against induced cross-stresses. These results broaden the knowledge about the physiological function of GSH, and suggest a practicable approach to improve the cold resistance of L. sanfranciscensis, a starter culture for sourdough, by the addition of GSH.     

Proteome‐base biomarkers in diabetes mellitus: Progress on biofluids' protein profiling using mass spectrometry

The worldwide number of individuals suffering from diabetes mellitus (DM) has been projected to rise from 171 million in 2000 to 366 million in 2030. Identification of specific biomarkers for prediction and monitoring of DM is needed not only for the adequate screening diagnosis but also to assist the design of interventions to prevent or delay progression of this pathology and its attendant complications. Proteomic methods based on MS hold special promise for the identification of novel biomarkers that might form the foundation for new clinical tests, but to date, their contribution has been somehow unfruitful. Indeed, from more than 300 proteins found differently modulated in body fluids from diabetic patients, approximately 50 were validated with other approaches like ELISA or Western blotting and the clinical trials are being initiated to employ biofluids’ proteomics (specifically urinary proteomics) in clinical decision. This review provides an overview of MS‐based applications in the identification of potential biomarkers for DM, emphasizing the methodological challenges involved.     

Anatomic site‐specific proteomic signatures of gastrointestinal stromal tumors

The gastrointestinal stromal tumor (GIST) is the most common mesenchymal malignancy of the gastrointestinal tract. Its clinical course ranges widely from a curable disorder to a highly malignant disease. Although its clinical and molecular characteristics depend on the anatomic site of origin, the molecular background of GIST arising in different anatomical site has not been studied yet. To investigate the proteomic background of GIST, we examined the proteomic features corresponding to the anatomic site of tumor origin. Comparison of the proteomic profile of gastric (23 cases) and small intestinal (9 cases) GIST by 2‐DE revealed 105 protein spots with significantly different intensity (p <0.01) between the two groups. Mass spectrometric study identified 68 distinct proteins for these 105 protein spots, including cancer‐associated ones such as prohibitin, pigment epithelium‐derived factor, and alpha‐actinin 4. The intensity of 37/105 (35.2%) protein spots was significantly concordant with the corresponding mRNA levels (p <0.01). Although both 2‐D DIGE and microarray experiments showed significant up‐regulation of vimentin expression in small intestinal GIST, Western blotting did not show a significant difference between the two groups. In conclusion, our study demonstrates the proteins specially expressed in GIST depending on their site of origin, as well as the unique advantage offered by use of proteomics to acquire such data. The identified proteins may provide clues to understanding the different characteristics of GIST depending on their site of origin.     

Integrative proteomics for the future US HUPO Fifth Annual Conference from genes to function 22-25 February 2009, San Diego, CA, USA

This report reviews the 5th US HUPO annual conference which was held in San Diego, California, from 22th to 25th February, 2009. The major goal of this year's meeting was to discuss future prospects within the field of proteomics and to push it towards integration with other synergizing technologies. Each day's sessions were guided by three broad themes: The Interface of Proteomics and Genomics, Systems Medicine, and Protein Structure and Modifications. As a summary this meeting has shown, that integration of multiple disciplines and high performance proteomics is needed to meet the demands of future proteomics.     

蛋白质组学研究进展及其在植物学研究中的应用

蛋白质组是后基因组时代出现的一个新兴研究领域。蛋白质组的研究主要是先通过双向凝胶电泳等方法分离蛋白质,然后用质谱等技术进行鉴定。它是后基因组重要的研究方向之一,具有巨大的商业应用前景,将会推动整个生命科学的发展。蛋白质组研究取得了很大进展,已经成为生物技术中的一个重要领域。     

Differentially expressed proteins during fat accumulation in bovine skeletal muscle

The objective of this study was to identify the proteins involved in bovine intramuscular fat (IMF) development. Global proteins were monitored in bovine skeletal muscle at muscle-developing versus IMF-increasing stages and with higher versus lower IMF scores, respectively. We identified two differentially expressed (two-fold or more) proteins at the IMF-increasing stage, up-regulated heat shock protein beta 1 (HSPB1) and down-regulated ATP synthase D chain (ATP5H), and two down-regulated proteins with higher IMF scores, carbonic anhydrase 2 (CA2) and myosin light chain 3 (MYL3). In vitro, after adipogenic differentiation, the mRNA expression of HSPB1 and ATP5H did not be changed, but that of CA2 and MYL3 decreased significantly (P < 0.05). After myogenic differentiation, the mRNA expression of HSPB1 increased significantly (P < 0.05), but expression of other genes did not vary. We suggested that CA2 and MYL3, which expressed down during adipogenic differentiation, could be indicative markers for negative regulation of IMF development.     

Identification of melanoma‐specific serological markers using proteomic analyses

The discovery of novel melanoma markers for not only early detection but also monitoring disease status is promising to improve the clinical outcome of patients. In the present study, we performed proteomic comparative analysis of plasma proteins between healthy volunteers and melanoma patients using NanoLC and MALDI‐TOF‐MS. As a result, we were successful in identifying nine proteins that were specifically expressed in melanoma plasma compared with healthy plasma, most of which had not previously been identified as plasma markers of melanoma. The mRNA expression levels of four proteins [pro‐platelet basic protein precursor (PPBP), serum amyloid A2 (SAA2), complement factor H‐related protein 1 precursor (FHR1), inter‐alpha‐trypsin inhibitor heavy chain H4 precursor (IAIH4)] were prominently up‐regulated in several melanoma cell lines compared with melanocytes. Moreover, two proteins (PPBP, SAA) were shown to be expressed in tumor specimens from melanoma patients. In the survival time analysis regarding melanoma patients, the semi‐quantified plasma PPBP levels were statistically negatively correlated with the survival time. Most interestingly, the significant survival benefit was seen in low PBPP level group (< index 20) versus high level (≥ index 20) group. The results suggest that PPBP might be a novel promising serological marker and a prognostic factor specific to melanomas.