Luteinizing hormone receptors are associated with non-receptor plasma membrane proteins on bovine luteal cell membranes.
Biophysical studies of the bovine luteinizing hormone (LH) receptor on luteal cell membranes suggest that this receptor may be part of a larger molecular weight structure. We have used 5-iodonaphthyl-1-azide (INA) to identify plasma membrane proteins near LH receptors on plasma membranes from bovine corpora lutea. Following binding of eosin isothiocyanate-derivatized ovine LH or human chorionic gonadotropin (hCG), five proteins with molecular weights of 71, 57, 55, 49 and 36 kDa were selectively derivatized with [125I]-INA following 2 h exposure at 22 degreesC to 514 nm light. However, there was no fluorescence energy transfer between LH receptors occupied by ovine LH or hCG indicating that LH receptors were not self-associated in these membrane preparations. Together these results suggest that, following hormone binding, single copies of the LH receptor may exist in large molecular weight structures that include non-receptor proteins.
Roess
D A
DA
Departments of Physiology and Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
Rahman
N A
NA
Munnelly
H
H
Meiklejohn
B I
BI
Brady
C J
CJ
Barisas
B G
BG
D000818:Animals; D001386:Azides; D002417:Cattle; D002462:Cell Membrane / Q000737:chemistry; D006063:Chorionic Gonadotropin; D003338:Corpus Luteum / Q000737:chemistry*; D004735:Energy Transfer; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007457:Iodine Radioisotopes; D007986:Luteinizing Hormone; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry; D008970:Molecular Weight; D011974:Receptors, LH / Q000737:chemistry*; D012756:Sheep
D001386:Azides; D006063:Chorionic Gonadotropin; D005456:Fluorescent Dyes; D007457:Iodine Radioisotopes; D008565:Membrane Proteins; D011974:Receptors, LH; C015298:iodonaphthylazide; D007986:Luteinizing Hormone