st-Ht31, a cell-permeable stearated peptide derived from the amphipathic helix domain of A-kinase anchoring proteins (AKAPs), effectively binds protein kinase A (PKA), impacting PKA's cellular interactions without altering its activity. Specifically, at a 50 µM concentration, it reduces PKA's membrane anchoring in BHK-21 fibroblast reporter assays. Moreover, st-Ht31 at concentrations of 1 and 3 µM decreases both capacitance and hyperactivation in mouse sperm, thereby inhibiting in vitro fertilization. Additionally, at 50 µM, this compound facilitates cholesterol export in BHK-21 cells and RAW 264.7 macrophages expressing ATP-binding cassette transporter 1 (ABCA1), showcasing its multifaceted cellular impacts.