Elucidation of the function of type 1 human methionine aminopeptidase during cell cycle progression
Elucidation of the function of type 1 human methionine aminopeptidase during cell cycle progression
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DOI：
10.1073/pnas.0608389103
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发表时间：
2006-11-28
影响因子：
11.1
通讯作者：
Liu, Jun O.
中科院分区：
文献类型：
--
作者：
Hu, Xiaoyi;Addlagatta, Anthony;Liu, Jun O.
N-末端起始剂甲硫氨酸的加工是从原核生物到真核生物保守的基本细胞过程。去除N-末端甲硫氨酸的酶被称为甲硫氨酸氨基肽酶（MetAP）。已显示人MetAP 2是内皮细胞增殖和血管生成所需的。然而，MetAP 1的生理功能仍然难以捉摸。在这份报告中，我们证明了以前为细菌和酵母MetAP 1开发的具有吡啶-2-羧酸核心结构的抑制剂家族也对人MetAP 1（HsMetAP 1）具有特异性，这一点通过酶测定和高分辨率X射线晶体学证实。用MetAP 1特异性抑制剂处理肿瘤细胞系导致细胞聚集在G（2）/M期，表明HsMetAP 1可能在G（2）/M期转变中起重要作用。HsMetAP 1的过表达，而不是HsMetAP 2，赋予细胞对抑制剂的抗性，并且抑制剂引起已知MetAP底物的N-末端甲硫氨酸的保留，表明HsMetAP 1是抑制剂的细胞靶点。此外，当HsMetAP 1被基因特异性siRNA敲低时，细胞在G（2）/M期表现出较慢的进展，这与MetAP 1抑制剂处理的细胞表型相似。重要的是，MetAP 1抑制剂能够诱导白血病细胞系的凋亡，推测是由于它们干扰G（2）/M期检查点。总之，这些结果表明，MetAP 1在细胞周期的G2/M期起着重要作用，并且它可以作为发现和开发新抗癌药物的有希望的靶点。
Processing of the N-terminal initiator methionine is an essential cellular process conserved from prokaryotes to eukaryotes. The enzymes that remove N-terminal methionine are known as methionine aminopeptidases (MetAPs). Human MetAP2 has been shown to be required for the proliferation of endothelial cells and angiogenesis. The physiological function of MetAP1, however, has remained elusive. in this report we demonstrate that a family of inhibitors with a core structure of pyridine-2-carboxylic acid previously developed for the bacterial and yeast MetAP1 is also specific for human MetAP1 (HsMetAP1), as confirmed by both enzymatic assay and high-resolution x-ray crystallography. Treatment of tumor cell lines with the MetAP1-specific inhibitors led to an accumulation of cells in the G(2)/M phase, suggesting that HsMetAP1 may play an important role in G(2)/M phase transition. Overexpression of HsMetAP1, but not HsMetAP2, conferred resistance of cells to the inhibitors, and the inhibitors caused retention of N-terminal methionine of a known MetAP substrate, suggesting that HsMetAP1 is the cellular target for the inhibitors. In addition, when HsMetAP1 was knocked down by gene-specific siRNA, cells exhibited slower progression during G(2)/M phase, a phenotype similar to cells treated with MetAP1 inhibitors. Importantly, MetAP1 inhibitors were able to induce apoptosis of leukemia cell lines, presumably as a consequence of their interference with the G(2)/M phase checkpoint. Together, these results suggest that MetAP1 plays an important role in G2/M phase of the cell cycle and that it may serve as a promising target for the discovery and development of new anticancer agents.