The Akt1-eNOS axis illustrates the specificity of kinase-substrate relationships in vivo.
The Akt1-eNOS axis illustrates the specificity of kinase-substrate relationships in vivo.
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DOI：
10.1126/scisignal.2000343
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发表时间：
2009-08-04
影响因子：
7.3
通讯作者：
Sessa WC
中科院分区：
文献类型：
--
作者：
Schleicher M;Yu J;Murata T;Derakhshan B;Atochin D;Qian L;Kashiwagi S;Di Lorenzo A;Harrison KD;Huang PL;Sessa WC
Akt1对许多体内功能至关重要；然而，细胞特异性底物的作用仍有待确定。在这里，我们研究了内皮型一氧化氮合酶（eNOS）作为Akt1底物的重要性，方法是产生Akt1缺陷小鼠（Akt1 - / -小鼠），这些小鼠携带eNOS上关键的Akt1磷酸化位点（丝氨酸1176）的敲入突变（丝氨酸到天门氨酸或丝氨酸到丙氨酸的替代），使该酶“构成活性”或“活性降低”。eNOS突变不影响Akt1−/−小鼠的几种表型；然而，Akt1 - / -小鼠出生后血管生成缺陷的特征可以通过Akt1 - / -小鼠与携带eNOS组成型活性形式的小鼠杂交来恢复，而不能通过携带不太活跃的eNOS突变体的小鼠杂交来恢复。这种基因拯救导致体内和体外缺氧诱导因子1α (HIF-1α)的稳定和HIF-1α应答基因的增加。因此，Akt1主要通过eNOS和no依赖性信号的磷酸化来调节血管生成。
Akt1 is critical for many in vivo functions; however, the cell-specific substrates responsible remain to be defined. Here, we examine the importance of endothelial nitric oxide synthase (eNOS) as an Akt1 substrate by generating Akt1-deficient mice (Akt1−/− mice) carrying knock-in mutations (serine to aspartate or serine to alanine substitutions) of the critical Akt1 phosphorylation site on eNOS (serine 1176) that render the enzyme “constitutively active” or “less active.” The eNOS mutations did not influence several phenotypes in Akt1−/− mice; however, the defective postnatal angiogenesis characteristic of Akt1−/− mice was rescued by crossing the Akt1−/− mice with mice carrying the constitutively active form of eNOS, but not by crossing with mice carrying the less active eNOS mutant. This genetic rescue resulted in the stabilization of hypoxia-inducible factor 1α (HIF-1α) and increased production of HIF-1α–responsive genes in vivo and in vitro. Thus, Akt1 regulates angiogenesis largely through phosphorylation of eNOS and NO-dependent signaling.