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Title

Mitochondrial phosphate transport during nutrient stimulation of INS-1E insulinoma cells
Authors
Quan, Xianglan
Das, Ranjan
Xu, Shanhua
Cline, Gary W
Wiederkehr, Andreas
Wollheim, Claes
Park, Kyu-Sang
Published in Molecular and Cellular Endocrinology. 2013, vol. 381, no. 1-2, p. 198-209
Abstract Here, we have investigated the role of inorganic phosphate (Pi) transport in mitochondria of rat clonal β-cells. In α-toxin-permeabilized INS-1E cells, succinate and glycerol-3-phosphate increased mitochondrial ATP release which depends on exogenous ADP and Pi. In the presence of substrates, addition of Pi caused mitochondrial matrix acidification and hyperpolarisation which promoted ATP export. Dissipation of the mitochondrial pH gradient or pharmacological inhibition of Pi transport blocked the effects of Pi on electrochemical gradient and ATP export. Knock-down of the phosphate transporter PiC, however, neither prevented Pi-induced mitochondrial activation nor glucose-induced insulin secretion. Using (31)P NMR we observed reduction of Pi pools during nutrient stimulation of INS-1E cells. Interestingly, Pi loss was less pronounced in mitochondria than in the cytosol. We conclude that matrix alkalinisation is necessary to maintain a mitochondrial Pi pool, at levels sufficient to stimulate energy metabolism in insulin-secreting cells beyond its role as a substrate for ATP synthesis.
Keywords (31)P NMR, ANT, As(i), DIC, DL-α-glycerol-3-phosphate, DL-αGP, Inorganic phosphate, KRB, Krebs–Ringer bicarbonate, Metabolism-secretion coupling, Mitochondrial membrane potential, Mitochondrial pH gradient, N,N,N′,N′-tetramethyl-p-phenylenediamine, P(i), P(i)C, Phosphate carrier, TMPD, adenine nucleotide translocator, dicarboxylate carrier, inorganic arsenate, inorganic phosphate, mitochondrial electrical potential, mitochondrial pH gradient, phosphate carrier, ΔpH(mito), Ψ(mito)
Identifiers
PMID: 23939247
Full text
Article (Published version) (1.9 MB) - document accessible for UNIGE members only Limited access to UNIGE
Structures
Faculté de médecine / Section de médecine fondamentale / Département de physiologie cellulaire et métabolisme
Citation
(ISO format) 		QUAN, Xianglan et al. Mitochondrial phosphate transport during nutrient stimulation of INS-1E insulinoma cells. In: Molecular and Cellular Endocrinology, 2013, vol. 381, n° 1-2, p. 198-209. https://archive-ouverte.unige.ch/unige:34265

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Deposited on : 2014-02-11

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