Liposomes bearing platelet proteins: a model for surface functions studies.
An improved procedure for the direct transfer of membrane proteins from human platelets to liposomes involving the treatment of platelets with linolenic acid was developed. The transfer of platelet proteins to liposomes prepared from the mixture of L-alpha-dimyristoyl-phosphatidylcholine/sphingomyelin in the molar ratio 80/20 appeared to be significantly enhanced compared with liposomes prepared from the same components mixed in other ratios. A wide range of platelet proteins was transferred, the most important being GPIb (170 kDa), GPIIb/IIIa (135 and 110 kDa). GPIV (90 kDa), GPIX (24 kDa) and the serotonin transporter (68 kDa). The recognition interactions between these proteoliposomes and specific protein antibodies clearly indicate that the non-invasive procedure used in this study ensured the reproducible transfer of platelet proteins without essentially altering their original conformation. The obtained results reveal also that the affinity of proteoliposomes to bind paroxetin was virtually the same as that of the native serotonin transporter. These results provide an indication of the possible use of such proteoliposomes as models to study at the molecular level the interaction of these proteins with their ligands.
Dalençon
F
F
Physico-Chimie des Surfaces et Innovation en Pharmacotechnie, URA CNRS 1218. Université Paris-Sud. Châtenay-Malabry, France.
Rosilio
V
V
Puisieux
F
F
Baszkin
A
A
Wautier
J L
JL
D001792:Blood Platelets / Q000737:chemistry* / Q000187:drug effects; D002352:Carrier Proteins / Q000097:blood; D004134:Dimyristoylphosphatidylcholine / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005614:Freeze Fracturing; D006801:Humans; D008081:Liposomes / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000097:blood; D026901:Membrane Transport Proteins; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D009419:Nerve Tissue Proteins; D017374:Paroxetine / Q000097:blood; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins; D013109:Sphingomyelins / Q000378:metabolism; D013499:Surface Properties; D017962:alpha-Linolenic Acid / Q000494:pharmacology
D002352:Carrier Proteins; D008081:Liposomes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019038:Platelet Glycoprotein GPIb-IX Complex; D010980:Platelet Membrane Glycoproteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D013109:Sphingomyelins; D017962:alpha-Linolenic Acid; D017374:Paroxetine; D004134:Dimyristoylphosphatidylcholine