论文
论文标题:Regulation of the mammalian-brain V-ATPase through ultraslow mode-switching
作者:Kosmidis, Eleftherios, Shuttle, Christopher G., Preobraschenski, Julia, Ganzella, Marcelo, Johnson, Peter J., Veshaguri, Salome, Holmkvist, Jesper, Møller, Mads P., Marantos, Orestis, Marcoline, Frank, Grabe, Michael, Pedersen, Jesper L., Jahn, Reinhard, Stamou, Dimitrios
期刊:Nature
发表时间:2022/11/23
数字识别码:10.1038/s41586-022-05472-9
摘要:Vacuolar-type adenosine triphosphatases (V-ATPases)1,2,3 are electrogenic rotary mechanoenzymes structurally related to F-type ATP synthases4,5. They hydrolyse ATP to establish electrochemical proton gradients for a plethora of cellular processes1,3. In neurons, the loading of all neurotransmitters into synaptic vesicles is energized by about one V-ATPase molecule per synaptic vesicle6,7. 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 homologues8 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.
2022年11月23,丹麦哥本哈根大学Dimitrios Stamou研究组在Nature上发表了文章Regulation of the mammalian-brain V-ATPase through ultraslow mode-switching,发现V-ATPases并不是连续转运质子,而是存在三种不同的作用模式,分别是质子泵模式(Proton-pumping)、失活模式(Inactive)以及质子泄漏模式(Proton-leaky),从单分子水平的揭开了V-ATPase的工作原理。