Date of Award
Bachelor of Science
hormones, fertility, protein, labs, cell
The human follicle stimulating hormone receptor (hFSHR) is a glycoprotein hormone receptor belonging to the g protein-coupled receptor family. It is important in both male and female reproductive processes; defects in hFSHR can lead to infertility, delayed puberty, reduced muscle bulk, and osteoporosis. Work in other labs has shown that GPCRs can be localized to microdomains located within the cell membrane called lipid rafts. These regions are highly resistant to detergents because of the high concentration of sphingolipids and cholesterol. Also within these domains, an intracellular protein, caveolin, is present. Our lab has shown that hFSHR also localizes to lipid raft domains. We hypothesize that interaction with caveolin is important in the raft residency of hFSHR through a putative caveolin binding motif (CBM). The interaction between caveolin and hFSHR in these microdomains may regulate intracellular pathways activated by the receptor. To test our hypothesis, we have constructed CBM mutants and are in the process of creating stable cell lines expressing the mutant receptors to study the effects of mutating the key phenylalanine residues of the CBM. Interestingly, wild type FSHR presents as a doublet on a western blot while the 479L only have a single band. We theorize that one of these bands may be a glycosylation variant however further investigation is required. The mutated receptors qualitatively show normal p44-MAPK signaling in response to FSH, indicating that they are reaching the cell surface and are capable of binding hormone and coupling to signaling partners. We have observed a subtle difference in downstream PKA targets between the mutant and wild type hFSHR, suggesting that there might be a difference in the ability to activate downstream targets. Studying the interaction between hFSHR and caveolin has the potential to develop new contraceptive antagonists and alternative agonists to regulate fertility.
Fleischer, Justin, "Caveolin Binding Motif Mutation Yields a Variance in Follicle Stimulating Hormone Receptor Signaling" (2017). Honors Theses. 246.