Interaction of lipophorin with the plasma membrane of locust flight muscles.
Binding of high-density lipophorin (HDLp) to a plasma membrane preparation of locust flight muscle tissue was studied using a radiolabelled ligand binding assay and ligand blotting techniques. Analysis at 33 degrees C of the concentration-dependent total binding of tritium-labelled HDLp ([3H]HDLp) to the membrane preparation revealed the presence of a single specific binding site with an equilibrium dissociation constant of Kd = 9 (+/- 2) X 10(-7) M and a maximal binding capacity of 84 (+/- 10) ng X (micrograms protein)-1. Unlabelled HDLp as well as unlabelled low-density lipophorin (LDLp) competed with [3H]HDLp for binding to the identified binding site. In addition, ligand blotting demonstrated that both HDLp and LDLp bind specifically to a 30-kDa protein in the plasma membrane preparation, suggesting the involvement of this protein in the binding of lipophorins to the isolated membranes. A possible relationship between the identified binding of lipophorins and the observed co-purification of lipophorin lipase activity with the plasma membranes is discussed.
Van Antwerpen
R
R
Department of Experimental Zoology, University of Utrecht.
Beekwilder
J
J
Van Heusden
M C
MC
Van der Horst
D J
DJ
Beenakkers
A M
AM
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005426:Flight, Animal; D006110:Grasshoppers / Q000378:metabolism* / Q000502:physiology; D008074:Lipoproteins; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism* / Q000648:ultrastructure
D002352:Carrier Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; C032830:lipophorin