Reps2: A cellular signaling and molecular trafficking nexus

Since its discovery in the late 1990s as a signaling molecule in the Ras/Ral pathway, Reps2 has emerged as an important player in receptor-mediated endocytosis. Reps2 contains Eps15 homology (EH) domains, proline-rich regions, and a coiled-coil domain that engage in several protein–protein interactions to coordinate the internalization of various receptors with molecular signaling. Reps2 has clinical importance as it suppresses the ability of its binding partner RalBP1 to transport chemotherapeutic drugs, such as doxorubicin, out of a cell. Reps2 is also dysregulated during the progression of prostate cancer and is a potential biomarker for breast and prostate cancer.