Localization of PTP-1B, SHP-2, and Src exclusively in rat brain mitochondria and functional consequences.
An immunodetection study of protein tyrosine phosphatase 1B (PTP-1B), SHP-2, and Src in isolated mitochondria from different rat tissues (brain, muscle, heart, liver, and kidney) revealed their exclusive localization in the brain. Given this result, we sought whether mitochondria respond to ATP and to the general tyrosine phosphatase inhibitor orthovanadate and found little or no change in the tyrosine phosphorylation profile of mitochondria from muscle, heart, liver, and kidney. In contrast, ATP induced an enhancement in the tyrosine-phosphorylated protein profile of brain mitochondria, which was further greatly enhanced with orthovanadate and which disappeared when Src was inhibited with two inhibitors: PP2 and PP1. Importantly, we found that in brain mitochondria, ATP addition induced Src autophosphorylation at Tyr-416 in its catalytic site, leading to its activation, whereas the regulatory Tyr-527 site remained unphosphorylated. Functional implications were addressed by measurements of the enzymatic activity of each of the oxidative phosphorylation complexes in brain mitochondria in the presence of ATP. We found an increase in complex I, III, and IV activity and a decrease in complex V activity, partially reversed by Src inhibition, demonstrating that the complexes are Src substrates. These results complemented and reinforced our initial study showing that respiration of brain mitochondria was partially dependent on tyrosine phosphorylation. Therefore, the present data suggest a possible control point in the regulation of respiration by tyrosine phosphorylation of the complexes mediated by Src auto-activation.
Arachiche
Amal
A
INSERM-U688 Physiopathologie Mitochondriale, University Victor Ségalen-Bordeaux 2, Bordeaux-Cedex, France.
Augereau
Olivier
O
Decossas
Marion
M
Pertuiset
Claire
C
Gontier
Etienne
E
Letellier
Thierry
T
Dachary-Prigent
Jeanne
J
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D044927:Electron-Transferring Flavoproteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D008928:Mitochondria / Q000201:enzymology*; D024101:Mitochondrial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009928:Organ Specificity / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D044927:Electron-Transferring Flavoproteins; D004791:Enzyme Inhibitors; D024101:Mitochondrial Proteins; D009419:Nerve Tissue Proteins; D000255:Adenosine Triphosphate; D016392:Proto-Oncogene Proteins pp60(c-src); D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; C516610:Ptpn1 protein, rat; C516727:Ptpn11 protein, rat