Regulation of the mammalian-brain V-ATPase through ultraslow mode-switching.
Regulation of the mammalian-brain V-ATPase through ultraslow mode-switching.
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通过超慢模式切换调节哺乳动物大脑 V-ATP 酶。
DOI：
10.1038/s41586-022-05472-9
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发表时间：
2022
期刊：
影响因子：
64.8
通讯作者：
Stam
中科院分区：
文献类型：
--
作者：
Kosmidis,Eleftherios;Shuttle,ChristopherG;Preobraschenski,Julia;Ganzella,Marcelo;Johnson,PeterJ;Veshaguri,Salome;Holmkvist,Jesper;Møller,MadsP;Marantos,Orestis;Marcoline,Frank;Grabe,Michael;Pedersen,JesperL;Jahn,Reinhard;Stam
Vacuolar-type adenosine triphosphatases (V-ATPases), –are electrogenic rotary mechanoenzymes structurally related to F-type ATP synthases,. They hydrolyse ATP to establish electrochemical proton gradients for a plethora of cellular processes,. In neurons, the loading of all neurotransmitters into synaptic vesicles is energized by about one V-ATPase molecule per synaptic vesicle,. To shed light on this bona fide single-molecule biological process, we investigated electrogenic proton-pumping by single mammalian-brain V-ATPases in single synaptic vesicles. Here we show that V-ATPases do not pump continuously in time, as suggested by observing the rotation of bacterial homologues and assuming strict ATP–proton coupling. Instead, they stochastically switch between three ultralong-lived modes: proton-pumping, inactive and proton-leaky. Notably, direct observation of pumping revealed that physiologically relevant concentrations of ATP do not regulate the intrinsic pumping rate. ATP regulates V-ATPase activity through the switching probability of the proton-pumping mode. By contrast, electrochemical proton gradients regulate the pumping rate and the switching of the pumping and inactive modes. A direct consequence of mode-switching is all-or-none stochastic fluctuations in the electrochemical gradient of synaptic vesicles that would be expected to introduce stochasticity in proton-driven secondary active loading of neurotransmitters and may thus have important implications for neurotransmission. This work reveals and emphasizes the mechanistic and biological importance of ultraslow mode-switching.
