| Summary: | 碩士 === 長庚大學 === 基礎醫學研究所 === 86 === ABSTRACT
Nucleophosmin/B23, is a majore nucleolar phosphoprotein which plays an important role in the cell proliferation. When cells are treated with an anti-tumor drug, such as actinomycin D, that inhibits cell growth or during the stationary phase of growth, nucleophosmin/B23 translocates from nucleolus to nucleoplasm. Recently, it was shown that ATP is required for this translocation and nucleophosmin/B23 itself is an ATP-binding protein. Examination of nucleophosmin/B23 amino acid sequence reveals two putative ATP binding sequences. To determine the possible ATP-binding site of nucleophosmin/B23, a series of deletion clones were constructed. Our results showned that deletion of the putative C-terminal ATP binding sites (D244-293) will cause little decrease of its ability to bind ATP. Deletion of the putative N-terminal ATP-binding site resulted in losing most of its ATP binding ability. The results suggest that nucleophosmin/B23 has two ATP binding sites and the N-terminal ATP-binding site is more important than C-terminal ATP binding site. Furthermore, nucleophosmin/B23 can form oligomer that may be essential for its function. We thus used deletion clones to identify the domains that are essential for oligomer formation. Our data showed that intra-molecular interaction with amino acids residues 10-50 and 90-131 is essential for oligomer formation. Domains that are responsible for the nucleolar localization of nucleophosmin/B23 are also being elucidated. Our result showed that amino acid 10-72 and 243-297 may be involved in nucleolar accumulation of nucleophosmin/B23.
|
|---|
