FIGURE 2.

Schematic representation of the most important functions of Ras, Rho, Rab, Ran, and Arf family members. Ras proteins are mainly involved in the activation of the Ras/RAF/MEK/ERK and PI3K-Akt signaling pathways, fundamental for cell survival, proliferation, and differentiation; receptor tyrosine kinase (RTK) (1). Rho family members are essentially associated with actin cytoskeleton remodeling, pivotal for cell migration and spreading (2). Rab proteins are key in ensuring the specificity of vesicular transport. Particularly, they also have an important role in the formation, distribution, and secretion of melanosomes from melanocytes and melanoma cells to keratinocytes. (3). Ran proteins regulate the transport of cargoes between nucleus and cytoplasm (4). Arf family proteins are key regulators of membrane traffic, controlling vesicle budding, tethering, and actin cytoskeleton organization (5).