RAB17 is a member of the RAS oncogene family and is classified as a small GTPase that plays a crucial role in intracellular membrane trafficking It is specifically expressed in epithelial cells and is involved in various cellular functions such as transcytosis, the directed movement of endocytosed material through the cell and its exocytosis from the plasma membrane at the opposite side. This process is mainly observed in epithelial cells and is important for the transcellular transport of substances like immunoglobulins from the basolateral surface to the apical surface. RAB17 is also implicated in the regulation of melanosome transport and release from melanocytes, which is critical for pigmentation in skin cells . Additionally, it has been suggested to regulate dendrite and dendritic spine development, which are important for neuronal function. The protein is involved in membrane trafficking through apical recycling endosomes in a post-endocytic step of transcytosis.