High-level expression of rabbit 15-lipoxygenase induces collapse of the mitochondrial pH gradient in cell culture.
A critical step in the development of mammalian erythroblasts into mature red blood cells is the extrusion of the nucleus, followed by intracellular degradation of the remaining organelles. It has been hypothesized that the breakdown of cellular organelles in rabbit reticulocytes is initiated by 15-lipoxygenase. In vitro, the purified rabbit reticulocyte 15-lipoxygenase binds and permeabilizes organellar membranes, thereby releasing the lumenal contents of the organelle. Here, we demonstrate that ectopic expression of 15-lipoxygenase leads to the collapse of the mitochondrial pH gradient in nonerythroid cells, using a novel reporter of mitochondrial pH, mito-pHluorin. No change in mitochondrial pH was observed with a mutant of 15-lipoxygenase that lacks enzymatic activity. These data demonstrate that 15-lipoxygenase is capable of disrupting the pH gradient maintained by mitochondria in living cells without additional factors specific for red blood cell development.
Vijayvergiya
Chetan
C
Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
De Angelis
Dino
D
Walther
Matthias
M
Kühn
Hartmut
H
Duvoisin
Robert M
RM
Smith
Deborah H
DH
Wiedmann
Martin
M
D000595:Amino Acid Sequence; D000818:Animals; D001093:Arachidonate 15-Lipoxygenase / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000235:genetics*; D004789:Enzyme Activation / Q000235:genetics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000201:enzymology / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D017384:Sequence Deletion; D014162:Transfection
D010446:Peptide Fragments; D011994:Recombinant Proteins; D001093:Arachidonate 15-Lipoxygenase