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Neuronal cell surface ATP synthase mediates synthesis of extracellular ATP and regulation of intracellular pH
San‑Li Xing*, Jie Yan*, Zhi‑Hua Yu† and Cui‑Qing Zhu*1
*State Key Laboratory of Medical Neurobiology and Department of Neurobiology, Shanghai Medical College, Fudan University, 138 YiXueYuan Road, Shanghai 200032, Peoples Republic of China, and †Shanghai Geriatric Institute of Chinese Medicine, 1199 Central Fuxing Road, Shanghai 200031, Peoples Republic of China
The ATP synthase is known to play important roles in ATP generation and proton translocation within mitochondria. Here, we now provide evidence showing the presence of functional ecto-ATP synthase on the neuronal surface. Immunoblotting revealed that the α, β subunits of ATP synthase F1 portion are present in isolated fractions of plasma membrane and biotin-labelled surface protein from primary cultured neurons; the surface distribution of α, β subunits was also confirmed by immunofluorescence staining. Moreover, α and β subunits were also found in fractions of plasma membrane and lipid rafts isolated from rat brain, and flow cytometry analysis showed α subunits on the surface of acutely isolated brain cells. Activity assays showed that the extracellular ATP generation of cultured neurons could be compromised by α, β subunit antibodies and ATP synthase inhibitors. pHi (intracellular pH) analysis demonstrated that at low extracellular pH, α or β subunit antibodies decreased pHi of primary cultured neurons. Therefore, ATP synthase on the surface of neurons may be involved in the machineries of extracellular ATP generation and pHi homoeostasis.
Key words: ATP generation, ATP synthase, intracellular pH, lipid raft, neuron, plasma membrane
Abbreviations: DMEM, Dulbecco's modified Eagle's medium, FBS, fetal bovine serum, pHi, intracellular pH, SD, Sprague–Dawley
1To whom correspondence should be addressed (email email@example.com).
Received 22 November 2009/28 April 2010; accepted 14 July 2010
Published as Cell Biology International Immediate Publication 14 July 2010, doi:10.1042/CBI20090441
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