Colocalization of hFSHR and Caveolin in the Lipid Raft

FSH plays a significant role in reproductive endocrinology for both men and women and is the key to understanding causes of, and possible treatment options for, infertility. FSH is a glycoprotein hormone that targets a g protein-coupled receptor (GPCR) on the cell membrane of granulosa and Sertoli cells in the ovaries and testes, respectively. The granulosa and Sertoli cells are responsible for ovarian follicular development, spermatogenesis, and estrogen production. GPCR are transmembrane proteins that exist within the lipid raft of the cell membrane. The function of other GPCR have been shown to be influenced by interactions with caveolin, an integral membrane protein within the lipid raft, which stimulates both localization and delocalization of signaling molecules and proteins within the lipid raft. The presence of the caveolin binding motif in hFSHR led to the hypothesis that caveolin and hFSHR colocalize within the lipid raft. To determine the relationship between caveolin and hFSHR, fluorescence microscopy was used. Human embryonic kidney 293 cells were transfected with a caveolin-green fluorescent fusion protein (cavGFP). After treating the cells with FSH in a time course from 5-30 minutes they were stained with anti-hFSHR 106.105 monoclonal antibody and imaged using a confocal microscope. Preliminary results show that caveolin and hFSHR colocalize in a hormone dependent manner. By examining the colocalization of the caveolin and FSHR in lipid rafts, we will gain a better understanding of the signaling pathway of FSH in order to find novel therapeutic targets for infertility treatments.