分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: The integrins, a family of transmembrane proteins, function in cell-to-cell and cell-to-extracellular matrix (ECM) adhesive interactions, and influence cell signaling of cell growth and differentiation. Expression of integrin 6 in three bladder cancer cell lines, HCV29, KK47 and YST1 were quantitatively analyzed by LC-MS using stable isotope labeling by amino acids in cell culture (SILAC), a simple and powerful proteomic strategy. The results showed that the non-invasive bladder cancer cell line KK47 expressed the highest level of integrin alpha 6. The expression of integrin alpha 6 in invasive bladder cancer cell line YTS1 was also higher than in normal bladder epithelial cell line HCV29. Furthermore, these results were confirmed by Western blotting, qPCR, immunohistochemistry and flow cytometry. Clinical data of mRNA 1TGA6 expression pattern from open-access database (www.oncomine.org) showed the same result during bladder cancer progression. All these indicated that integrin alpha 6 is associated with the invasion progress of the bladder cancer. The preliminary data in this study may sparkle the fundamental role of integrin 6 in the research of bladder cancer.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: The individual roles of three chloroplast CPN60 protomers (CPN60 alpha, CPN60 beta 1, and CPN60 beta 2) and whether and how they are assembled into functional chaperonin complexes are investigated in Chlamydomonas reinhardtii. Protein complexes containing all three potential subunits were identified in Chlamydomonas, and their co-expression in Escherichia coli yielded a homogeneous population of oligomers containing all three subunits (CPN60 alpha beta 1 beta 2), with a molecular weight consistent with a tetradecameric structure. While homo-oligomers of CPN60 beta could form, they were dramatically reduced when CPN60 alpha was present and homo-oligomers of CPN60 beta 2 were readily changed into hetero-oligomers in the presence of ATP and other protomers. ATP hydrolysis caused CPN60 oligomers to disassemble and drove the purified protomers to reconstitute oligomers in vitro, suggesting that the dynamic nature of CPN60 oligomers is dependent on ATP. Only hetero-oligomeric CPN60 alpha beta 1 beta 2, containing CPN60 alpha, CPN60 beta 1, and CPN60 beta 2 subunits in a 5: 6: 3 ratio, cooperated functionally with GroES. The combination of CPN60 alpha and CPN60 beta subunits, but not the individual subunits alone, complemented GroEL function in E. coli with subunit recognition specificity. Down-regulation of the CPN60 alpha subunit in Chlamydomonas resulted in a slow growth defect and an inability to grow autotrophically, indicating the essential role of CPN60 alpha in vivo.