Structural homologies in the lutropin/human choriogonadotropin receptor and the follitropin receptor on porcine granulosa cells.
In order to examine the structure of the human choriogonadotropin (hCG) receptor and the follitropin (FSH) receptor on porcine granulosa cells, the hormone receptors were photoaffinity-labeled or affinity-cross-linked. The resulting hormone-receptor complexes were analyzed by alkaline cleavage of cross-links, reduction of disulfides, and peptide maps. The results revealed striking similarities in the structure of the hormone receptors. Both appear to be oligomeric; the hCG receptor has at least four components of 18, 24, 28, and 34 kDa, whereas the FSH receptor shows three distinct components of 18, 22, and 34 kDa. The 24- and the 22-kDa components are the sites for the primary photoaffinity labeling or affinity cross-linking by hCG and FSH, respectively. These components were linked by intercomponent disulfides. Reduction of cross-linked complexes revealed that in the hCG receptor the 24-, the 28-, and the 34-kDa components were disulfide-linked sequentially in a linear form as were the 22-, the 18-, and the 34-kDa components in the FSH receptor. The peptide maps of cross-linked hCG-receptor and FSH-receptor complexes, however, were distinct, indicating that the hCG receptor and the FSH receptor were not identical.
D000345:Affinity Labels; D000818:Animals; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D004220:Disulfides / Q000032:analysis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D006107:Granulosa Cells / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007986:Luteinizing Hormone / Q000378:metabolism*; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011962:Receptors, FSH; D011974:Receptors, LH; D013552:Swine
D000345:Affinity Labels; D006063:Chorionic Gonadotropin; D004220:Disulfides; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D011962:Receptors, FSH; D011974:Receptors, LH; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone