An amphitropic cAMP-binding protein in yeast mitochondria. 2. Phospholipid nature of the membrane anchor.
We describe the first example of a mitochondrial protein with a covalently attached phosphatidylinositol moiety acting as a membrane anchor. The protein can be metabolically labeled with both stearic acid and inositol. The stearic acid label is removed by phospholipase D whereupon the protein with the retained inositol label is released from the membrane. This protein is a cAMP receptor of the yeast Saccharomyces cerevisiae and tightly associated with the inner mitochondrial membrane. However, it is converted into a soluble form during incubation of isolated mitochondria with Ca2+ and phospholipid (or lipid derivatives). This transition requires the action of a proteinaceous, N-ethylmaleimide-sensitive component of the intermembrane space and is accompanied by a decrease in the lipophilicity of the cAMP receptor. We propose that the component of the intermembrane space triggers the amphitropic behavior of the mitochondrial lipid-modified cAMP-binding protein through a phospholipase activity.
Müller
G
G
Institut für Pathologie und Rechtsmedizin Universität Ulm, München, Federal Republic of Germany.
Bandlow
W
W
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002373:Cyclic AMP Receptor Protein; D005656:Fungal Proteins / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism; D010740:Phospholipases / Q000378:metabolism; D011953:Receptors, Cyclic AMP / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000648:ultrastructure*; D013552:Swine; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism
D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D005656:Fungal Proteins; D010716:Phosphatidylinositols; D011953:Receptors, Cyclic AMP; D010740:Phospholipases; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate