Nonspecific lipid transfer protein (sterol carrier protein 2) is bound to rat liver mitochondria: its role in spontaneous intermembrane phospholipid transfer.
In the present study we have investigated the transfer of phospholipids between vesicles and rat liver mitochondria. Transfer was measured by electron paramagnetic resonance spectroscopy using vesicles that contained spin-labeled phospholipids. A spontaneous transfer was observed which could be strongly inhibited by treating the mitochondria with the thiol reagent mersalyl. Transfer was also greatly reduced after a saline wash of the mitochondria; the transfer activity was then recovered in the wash. This activity was inhibited by tryptic digestion and mersalyl. By gel chromatography, enzyme immunoassay and immunoblotting it was demonstrated that the activity in the wash was due to the nonspecific lipid transfer protein (sterol carrier protein 2). We could estimate that up to 85% of the spontaneous phospholipid transfer between vesicles and rat liver mitochondria was mediated by this transfer protein.
D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008634:Mersalyl / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D010940:Plant Proteins; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013438:Sulfhydryl Compounds / Q000502:physiology
D002352:Carrier Proteins; D010743:Phospholipids; D010940:Plant Proteins; D013438:Sulfhydryl Compounds; C072087:sterol carrier proteins; D008634:Mersalyl; D011189:Potassium Chloride