Mitochondrial phosphate transport during nutrient stimulation of INS-1E insulinoma cells

Quan, Xianglan; Das, Ranjan; Xu, Shanhua; Cline, Gary W; Wiederkehr, Andreas; Wollheim, Claes; Park, Kyu-Sang

doi:10.1016/j.mce.2013.08.003

Scientific article

English

Mitochondrial phosphate transport during nutrient stimulation of INS-1E insulinoma cells

Contributors

Quan, Xianglan; Das, Ranjan; Xu, Shanhua; Cline, Gary W; Wiederkehr, Andreas; Wollheim, Claes; Park, Kyu-Sang

Published in

Molecular and cellular endocrinology, vol. 381, no. 1-2, p. 198-209

Publication date

2013

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)

UNIGE affiliation entities

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. doi: 10.1016/j.mce.2013.08.003

Article (Published version)

Identifiers

PID : unige:34265
DOI : 10.1016/j.mce.2013.08.003
PMID : 23939247

Journal ISSN

0303-7207

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Mitochondrial phosphate transport during nutrient stimulation of INS-1E insulinoma cells

Contributors

Published in

Publication date

Abstract

Keywords

UNIGE affiliation entities

Citation (ISO format)

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Journal ISSN

Technical informations

Creation

First validation

Update

Status update

Last indexation