Rac1 is a small GTPase protein that plays a crucial role in various cellular processes, including cell migration, adhesion, and growth. It is part of the Rho family of GTPases, which are known for their ability to regulate the cytoskeleton, the structure that helps maintain a cell's shape and enables movement. Rac1 is activated by exchanging GDP for GTP, leading to the activation of downstream signaling pathways. These pathways are important for processes such as immune response and neuronal development. Dysregulation of Rac1 has been linked to various diseases, including cancer and neurodegenerative disorders.