Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada.
Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK.
Science. 2020 Mar 13;367(6483):1240-1246. doi: 10.1126/science.aaz2924.
In neurons, the loading of neurotransmitters into synaptic vesicles uses energy from proton-pumping vesicular- or vacuolar-type adenosine triphosphatases (V-ATPases). These membrane protein complexes possess numerous subunit isoforms, which complicates their analysis. We isolated homogeneous rat brain V-ATPase through its interaction with SidK, a effector protein. Cryo-electron microscopy allowed the construction of an atomic model, defining the enzyme's ATP:proton ratio as 3:10 and revealing a homolog of yeast subunit f in the membrane region, which we tentatively identify as RNAseK. The c ring encloses the transmembrane anchors for cleaved ATP6AP1/Ac45 and ATP6AP2/PRR, the latter of which is the (pro)renin receptor that, in other contexts, is involved in both Wnt signaling and the renin-angiotensin system that regulates blood pressure. This structure shows how ATP6AP1/Ac45 and ATP6AP2/PRR enable assembly of the enzyme's catalytic and membrane regions.
在神经元中，神经递质装载到突触小泡中使用质子泵泡或液泡型三磷酸腺苷酶 (V-ATPase) 的能量。这些膜蛋白复合物具有许多亚基同工型，这使得它们的分析变得复杂。我们通过与效应蛋白 SidK 的相互作用，从大鼠脑中分离出了同质的 V-ATPase。冷冻电子显微镜允许构建原子模型，确定酶的 ATP:质子比为 3:10，并在膜区域中发现了酵母亚基 f 的同源物，我们暂时将其鉴定为 RNAseK。c 环包围了裂解的 ATP6AP1/Ac45 和 ATP6AP2/PRR 的跨膜锚，后者是（前）肾素受体，在其他情况下，它参与 Wnt 信号和调节血压的肾素-血管紧张素系统。该结构显示了 ATP6AP1/Ac45 和 ATP6AP2/PRR 如何使酶的催化和膜区域组装在一起。
