MOE Key Laboratory of Arid and Grassland Ecology, Institute of Biophysics, Lanzhou University, Lanzhou 730000, P.R. China.
Structure. 2011 Apr 13;19(4):515-22. doi: 10.1016/j.str.2011.01.018.
AMP-activated protein kinase (AMPK) is a heterotrimeric complex composed of α catalytic subunit, β scaffolding subunit, and γ regulatory subunit with critical roles in maintaining cellular energy homeostasis. However, the molecular architecture of the intact complex and the allostery associated with the adenosine binding-induced regulation of kinase activity remain unclear. Here, we determine the three-dimensional reconstruction and subunit organization of the full-length rat AMPK (α1β1γ1) through single-particle electron-microscopy. By comparing the structures of AMPK in ATP- and AMP-bound states, we are able to visualize the sequential conformational changes underlying kinase activation that transmits from the adenosine binding sites in the γ subunit to the kinase domain of the α subunit. These results not only make substantial revision to the current model of AMPK assembly, but also highlight a central role of the linker sequence of the α subunit in mediating the allostery of AMPK.
AMP 激活的蛋白激酶（AMPK）是一种异三聚体复合物，由α催化亚基、β支架亚基和γ调节亚基组成，在维持细胞能量稳态中起着关键作用。然而，完整复合物的分子结构以及与腺苷结合诱导激酶活性调节相关的变构作用仍不清楚。在这里，我们通过单颗粒电子显微镜确定了全长大鼠 AMPK（α1β1γ1）的三维重构和亚基组织。通过比较 AMPK 在 ATP 和 AMP 结合状态下的结构，我们能够可视化激酶激活的顺序构象变化，这种变化从γ亚基的腺苷结合位点传递到α亚基的激酶结构域。这些结果不仅对 AMPK 组装的现有模型进行了实质性的修正，而且还突出了α亚基的连接序列在调节 AMPK 的变构作用中的核心作用。
