Sakata K, Fukuchi-Shimogori T, Kashiwagi K, Igarashi K
Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263, Japan.
Biochem Biophys Res Commun. 1997 Sep 18;238(2):415-9. doi: 10.1006/bbrc.1997.7266.
Antizyme is a negative regulator of ornithine decarboxylase (ODC) and of polyamine transport. Regions of antizyme necessary for the negative regulation of polyamine transport were determined by transfecting ODC-overproducing EXOD-1 cells with mutant antizyme genes containing different size deletions in the NH2- and COOH-terminal of antizyme (AZ69-227). When peptide 119-144 or peptide 211-216, which are responsible for the binding of ODC, were deleted from antizyme, the mutant antizyme could not reverse the inhibition of growth of EXOD-1 cells produced by spermine. In parallel with the decrease in antizyme effect on cell growth, spermine transport activity and the accumulation of spermine in EXOD-1 cells were not significantly altered by the mutant antizyme, whereas wild-type antizyme decreased spermine transport and accumulation. When the peptide 69-118, which is responsible for the degradation of ODC, was deleted from antizyme, the mutant antizyme showed a smaller effect compared with the normal antizyme in terms of the inhibition of spermine transport and the recovery from the spermine inhibition of cell growth. The results indicate that regions 119-144 and 211-216 in antizyme are necessary for the negative regulation of polyamine transport and that these regions overlap with ODC binding sites.
抗酶是鸟氨酸脱羧酶（ODC）和多胺转运的负调节因子。通过用在抗酶（AZ69 - 227）的NH2端和COOH端含有不同大小缺失的突变抗酶基因转染过量产生ODC的EXOD - 1细胞，确定了多胺转运负调节所需的抗酶区域。当负责ODC结合的肽119 - 144或肽211 - 216从抗酶中缺失时，突变抗酶无法逆转精胺对EXOD - 1细胞生长的抑制作用。与抗酶对细胞生长作用的降低相一致，突变抗酶对EXOD - 1细胞中的精胺转运活性和精胺积累没有显著改变，而野生型抗酶降低了精胺的转运和积累。当负责ODC降解的肽69 - 118从抗酶中缺失时，就精胺转运的抑制以及从精胺对细胞生长的抑制中恢复而言，突变抗酶与正常抗酶相比显示出较小的作用。结果表明，抗酶中的区域119 - 144和211 - 216是多胺转运负调节所必需的，并且这些区域与ODC结合位点重叠。
