Functional Ca2+ channel produced by purified platelet membrane glycoprotein IIB-IIIA complex incorporated into planar phospholipid bilayer.
The ability of the platelet membrane glycoprotein (GP) IIb-IIIa complex to function as a Ca2+ channel was investigated by electrophysiological methods. The GPIIb-IIIa complex was purified with an electrically silent detergent, CHAPS, and reconstituted into liposomes. After incorporation of these liposomes to a planar phospholipid bilayer, Ba(2+)-permeable channel currents were detected. Since neither residual detergent nor dissociated GPIIb and IIIa produced any currents, the observed channel currents were attributed to the GPIIb-IIIa complex. These channel currents showed similar electrical properties with the Ca2+ channel previously described in platelet plasma membrane; a single channel conductance of approximately 10 pS in 53 mM Ba2+ solution and voltage-independency. It was concluded that the purified GPIIb-IIIa complex can act as a divalent cation-permeable channel in the artificial phospholipid bilayer.
Fujimoto
T
T
Department of Internal Medicine, Hiroshima University, Japan.
Fujimura
K
K
Kuramoto
A
A
D015220:Calcium Channels / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008051:Lipid Bilayers; D008564:Membrane Potentials; D010980:Platelet Membrane Glycoproteins / Q000302:isolation & purification / Q000502:physiology*; D013329:Structure-Activity Relationship; D013917:Thrombin / Q000494:pharmacology
D015220:Calcium Channels; D008051:Lipid Bilayers; D010980:Platelet Membrane Glycoproteins; D013917:Thrombin