RESUMO
Hax-1 is a protein involved in regulation of different cellular processes, but its properties and exact mechanisms of action remain unknown. In this work, using purified, recombinant Hax-1 and by applying an in vitro autoradiography assay we have shown that this protein binds Ca2+. Additionally, we performed structure prediction analysis which shows that Hax-1 displays definitive structural features, such as two α-helices, short ß-strands and four disordered segments.
Assuntos
Cálcio/metabolismo , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Engenharia de Proteínas/métodos , Proteínas Adaptadoras de Transdução de Sinal/química , Autorradiografia , Proteínas de Transporte/genética , Proteínas de Transporte/isolamento & purificação , Escherichia coli/genética , Peptídeos e Proteínas de Sinalização Intracelular , Conformação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Tiorredoxinas/genética , Tiorredoxinas/metabolismoRESUMO
BACKGROUND: HAX-1 has been described as a protein potentially involved in carcinogenesis and especially metastasis. Its involvement in regulation of apoptosis and cell migration along with some data indicating its overexpression in cancer cell lines and tumors suggests that HAX-1 may play a role in neoplastic transformation. Here we present the first systematic analysis of HAX-1 expression in several solid tumors. METHODS: Using quantitative RT-PCR, we have determined the mRNA levels of HAX1 splice variant I in several solid tumors. We have also analyzed by semiquantitative and quantitative RT-PCR the expression of five HAX-1 splice variants in breast cancer samples and in normal tissue from the same individuals. Quantitative PCR was also employed to analyze the effect of estrogen on HAX1 expression in breast cancer cell line. Immunohistochemical analysis of HAX-1 was performed on normal and breast cancer samples. RESULTS: The results reveal statistically important HAX1 up-regulation in breast cancer, lung cancer and melanoma, along with some minor variations in the splicing pattern. HAX-1 up-regulation in breast cancer samples was confirmed by immunohistochemical analysis, which also revealed an intriguing HAX-1 localization in the nuclei of the tumor cells, associated with strong ER status. CONCLUSION: HAX-1 elevated levels in cancer tissues point to its involvement in neoplastic transformation, especially in breast cancer. The connection between HAX-1 nuclear location and ER status in breast cancer samples remains to be clarified.
