The F1-ATPase beta-subunit is the putative enterostatin receptor.
It has been suggested that the F1-ATPase beta-subunit is the enterostatin receptor. We investigated the binding activity of the purified protein with a labeled antagonist, beta-casomorphin1-7, in the absence and presence of cold enterostatin. 125I-beta-casomorphin1-7 weakly binds to the rat F1-ATPase beta-subunit. Binding was promoted by low concentrations of cold enterostatin but displaced by higher concentrations. To study the relationship between binding activity and feeding behavior, we examined the ability of a number of enterostatin analogs to affect beta-casomorphin1-7 binding to the F1-ATPase beta-subunit. Peptides that suppressed food intake promoted beta-casomorphin1-7 binding whereas peptides that stimulated food intake or did not affect the food intake displaced beta-casomorphin1-7 binding. Surface plasmon resonance measurements show that the beta-subunit of F1-ATPase binds immobilized enterostatin with a dissociation constant of 150 nM, where no binding could be detected for the assembled F1-ATPase complex. Western blot analysis showed the F1-ATPase beta-subunit was present on plasma and mitochondrial membranes of rat liver and amygdala. The data provides evidence that the F1-ATPase beta-subunit is the enterostatin receptor and suggests that enterostatin and beta-casomorphin1-7 bind to distinct sites on the protein.
Park
Miejung
M
Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
Lin
Ling
L
Thomas
Sonyja
S
Braymer
Hugh D
HD
Smith
Pamela M
PM
Harrison
David H T
DH
York
David A
DA
D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D003089:Colipases / Q000378:metabolism* / Q000494:pharmacology; D004723:Endorphins / Q000737:chemistry; D004792:Enzyme Precursors; D005247:Feeding Behavior / Q000187:drug effects; D007425:Intracellular Membranes / Q000201:enzymology; D008297:Male; D008930:Mitochondria, Liver / Q000648:ultrastructure; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism* / Q000494:pharmacology; D009842:Oligopeptides / Q000378:metabolism / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry; D011498:Protein Precursors / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*
D003089:Colipases; D004723:Endorphins; D004792:Enzyme Precursors; D009842:Oligopeptides; D010446:Peptide Fragments; D011498:Protein Precursors; D011956:Receptors, Cell Surface; C117600:enterostatin receptor; C041128:beta-casomorphin 7; C037107:procolipase; C497342:ATP synthase beta subunit, rat; D025261:Mitochondrial Proton-Translocating ATPases