Cdc42, a small GTPase, regulates Actin polymerization, elongation of cell shape and cell signaling through interactions with many different downstream effector proteins, most of which contain a Cdc42-binding motif known as a CRIB domain. Cdc42EP2 (Cdc42 effector protein 2), also known as BORG1 or CEP2, is a 210 amino acid intracytoplasmic protein that localizes to both the cytoplasm and the cytoskeleton and contains one CRIB domain. Highly expressed in heart and present at lower levels in liver and pancreas, Cdc42EP2 interacts with Cdc42 and is thought to be involved in the organization of the Actin cytoskeleton and may also influence Actin filament assembly and overall cell shape.