ErbB2, a member of the receptor tyrosine kinase family, is frequently over-expressed in breast cancer. Proteolysis ofthe extracellular domain of ErbB2 results in constitutive activation of ErbB2 kinase. Recent study r...ErbB2, a member of the receptor tyrosine kinase family, is frequently over-expressed in breast cancer. Proteolysis ofthe extracellular domain of ErbB2 results in constitutive activation of ErbB2 kinase. Recent study reported that ErbB2is found in the nucleus. Here, we showed that ErbB2 is imported into the nucleus through a nuclear localization signal(NLS)-mediated mechanism. The NLS sequence KRRQQKIRKYTMRR (aa655-668) contains three clusters of basicamino acids and it is sufficient to target GFP into the nucleus. However, mutation in any basic amino acid cluster of thisNLS sequence significantly affects its nuclear localization. Furthermore, it was found that this NLS is essential for thenuclear localization of ErbB2 since the intracellular domain of Erb2 lacking NLS completely abrogates its nucleartranslocation. Taken together, our study identified a novel nuclear localization signal and reveals a novel mechanismunderlying ErbB2 nuclear trafficking and localization.展开更多
Variable Charge X/Y (VCX/Y) is a human testis-specific gene family that localized on X and Y chromosomes. In this study, VCY protein was expressed in E. coli in the form of glutathione-S-transferase (GST) fusion prote...Variable Charge X/Y (VCX/Y) is a human testis-specific gene family that localized on X and Y chromosomes. In this study, VCY protein was expressed in E. coli in the form of glutathione-S-transferase (GST) fusion protein. With the purified fusion protein as antigen, the anti-GST-VCY antibody was generated and the localization of VCY protein in human testis was determined by immunohistochemistry. In the testis seminiferous epithelium. VCY proteins were highly expressed in nuclei of germ cells. Using propidium iodide staining and green fluorescent protein (GFP) tag technologies, VCY and VCX-8r proteins were mainly localized in the uucleoli of COST cells. In addition, the colocalization for VCY and VCX-8r in COS7 cells was also observed. With VCY cDNA as bait, a cDNA fragment of acidic ribosomal protein PO was obtained using yeast two-hybrid system. All the information above indicates that VCX/Y protein family might be involved in the regulation of ribosome assembly (hiring spermatogenesis.展开更多
基金This work was supported by Hi-Tech Research and Development Program of China(2004AA215260).
文摘ErbB2, a member of the receptor tyrosine kinase family, is frequently over-expressed in breast cancer. Proteolysis ofthe extracellular domain of ErbB2 results in constitutive activation of ErbB2 kinase. Recent study reported that ErbB2is found in the nucleus. Here, we showed that ErbB2 is imported into the nucleus through a nuclear localization signal(NLS)-mediated mechanism. The NLS sequence KRRQQKIRKYTMRR (aa655-668) contains three clusters of basicamino acids and it is sufficient to target GFP into the nucleus. However, mutation in any basic amino acid cluster of thisNLS sequence significantly affects its nuclear localization. Furthermore, it was found that this NLS is essential for thenuclear localization of ErbB2 since the intracellular domain of Erb2 lacking NLS completely abrogates its nucleartranslocation. Taken together, our study identified a novel nuclear localization signal and reveals a novel mechanismunderlying ErbB2 nuclear trafficking and localization.
基金supported by grants from the Special Fund for Major State Basic Research Project(No.G1999055901)National Natural Sciences Foundation of China(No.30240019)+1 种基金National High Technology Research and Technology of China(No.2001AA221131)State Ministry of Science and Technology Program(No.2002BA711A011.
文摘Variable Charge X/Y (VCX/Y) is a human testis-specific gene family that localized on X and Y chromosomes. In this study, VCY protein was expressed in E. coli in the form of glutathione-S-transferase (GST) fusion protein. With the purified fusion protein as antigen, the anti-GST-VCY antibody was generated and the localization of VCY protein in human testis was determined by immunohistochemistry. In the testis seminiferous epithelium. VCY proteins were highly expressed in nuclei of germ cells. Using propidium iodide staining and green fluorescent protein (GFP) tag technologies, VCY and VCX-8r proteins were mainly localized in the uucleoli of COST cells. In addition, the colocalization for VCY and VCX-8r in COS7 cells was also observed. With VCY cDNA as bait, a cDNA fragment of acidic ribosomal protein PO was obtained using yeast two-hybrid system. All the information above indicates that VCX/Y protein family might be involved in the regulation of ribosome assembly (hiring spermatogenesis.
