Translocation to rat liver mitochondria of phosphatidate phosphohydrolase.
When a particle-free supernatant fraction from rat liver was incubated at 37 degrees C with mitochondria and oleate, some of the enzyme phosphatidate phosphohydrolase (PAP), initially present in the particle-free supernatant, was recovered, after the incubation, bound to mitochondria. This translocation of PAP from cytosol to mitochondria was stimulated by oleate or palmitate in a similar fashion to the stimulation of translocation of PAP to endoplasmic reticulum [Martin-Sanz, Hopewell & Brindley (1984) FEBS Lett. 175, 284-288]. Translocation of PAP from particle-free supernatant to a partially purified mitochondrial-outer-membrane preparation was also stimulated by oleate. More PAP was bound to a mitochondrial-outer-membrane fraction washed in 0.5 M-NaCl before resuspension in sucrose than to a sucrose-washed mitochondrial-outer-membrane preparation. In contrast, washing of microsomal membranes in 0.5 M-NaCl did not enhance the binding of PAP to these membranes. PAP also binds to phosphatidate-loaded mitochondria or microsomes (microsomal fractions). In the experimental system employed, more PAP bound to mitochondria loaded with phosphatidate than to microsomes loaded with phosphatidate. The results are discussed in relation to the role of mitochondrial phosphatidate in liver lipid metabolism.
Freeman
M
M
Department of Biochemistry, University of Nottingham Medical School, Queens Medical Centre, U.K.
Mangiapane
E H
EH
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003600:Cytosol / Q000201:enzymology; D007425:Intracellular Membranes / Q000201:enzymology; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000494:pharmacology; D010711:Phosphatidate Phosphatase / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D009829:Oleic Acids; D010169:Palmitic Acids; D010712:Phosphatidic Acids; D019301:Oleic Acid; D019308:Palmitic Acid; D009251:NADPH-Ferrihemoprotein Reductase; D010744:Phosphoric Monoester Hydrolases; D010711:Phosphatidate Phosphatase