Human fertility is dependent on the binding of follicle-stimulating hormone (FHS) to the human FSH receptor (hFSHR). This signaling translates into downstream effects such as spermatogenesis, follicular development, and hormone regulation. This project focuses on the identification of unknown proteins that interact with the hFSHR during FSH signaling. Currently, the hFSHR is targeted in female contraceptive treatments as it has specific actions on reproductive organs e.g. ovarian tissue, without having much effect on peripheral tissues. To understand the actions of FSHR it is necessary to identify the numerous intracellular signaling pathways and interacting proteins associated with its activation. We are interested in learning more about which specific proteins interact with hFSHR and whether the proteins that interact with FSHR change over time with FSH treatment. These interacting proteins may be transient and only associate with the hFSHR for short periods. Due to the possibility of brief interactions, proteins surrounding the receptor must be labeled and then identified. The identification and quantitative categorization of proteins in the vicinity of the hFSHR will be accomplished using the APEX assay. Proteins identified in this research could be possible targets for future infertility and contraceptive treatments.