A novel acidic form of the phosphatidylinositol transfer protein is preferentially retained in permeabilized Swiss mouse 3T3 fibroblasts.
By use of indirect immunofluorescence it was shown that phophatidylinositol transfer protein (PI-TP) remains associated with the Golgi system of Swiss mouse 3T3 fibroblasts after permeabilization with streptolysin O. By Western blot analysis it was demonstrated that intact cells contain the phosphatidylinositol-bound form of PI-TP (pI 5.5) and a novel more acidic form of PI-TP (pI 5.4) in approximately equal amounts. After permeabilization, about 50% of the PI-TP was retained in the cells with an enrichment of the pH 5.4 form relative to the pH 5.5 form; the opposite was observed for the PI-TP released into the medium. Subfractionation of cell homogenates by centrifugation provided evidence that a distinct amount of PI-TP is strongly bound to the membrane fraction with the pH 5.4 form more prominently present than the pH 5.5 form.
Centre for Biomembranes and Lipid Enzymology, University of Utrecht, The Netherlands.
K J
KJ
de Vries
A
A
Momchilova-Pankova
G T
GT
Snoek
K W
KW
Wirtz
D016475:3T3 Cells; D000818:Animals; D001426:Bacterial Proteins; D015153:Blotting, Western; D002352:Carrier Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D002463:Cell Membrane Permeability; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008565:Membrane Proteins; D051379:Mice; D008970:Molecular Weight; D010716:Phosphatidylinositols / Q000378:metabolism; D049294:Phospholipid Transfer Proteins; D013301:Streptolysins
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D049294:Phospholipid Transfer Proteins; D013301:Streptolysins; C025964:streptolysin O; D007770:L-Lactate Dehydrogenase