Exocytosis is crucial in membrane trafficking and it mediates hormone and neurotransmitter secretion out of the cell, as well as the incorporation of membrane proteins and lipids to the plasma membrane. It is crucial for cell-cell communication, cell growth and cell polarity. The exocyst complex is a multi-protein complex that consists of Sec3, Sec5, Sec6, Sec8, Sec10, Sec15, Exo70 and Exo84, and is essential for targeting exocytic vesicles to specific docking sites on the plasma membrane. The exocyst complex inhibits tubulin polymerization in vitro, suggesting that the exocyst complex is important for modulating the microtubule dynamics that underlie exocytosis. Exo84 (Exocyst complex 84 kDa subunit), also known as Exocyst complex component 8, is a 725 amino acid protein that is one of eight protein subunits composing the mammalian exocyst complex. Both Exo84 and Sec5 are effector targets for active Ral GTPases, which are responsible for regulating exocyst complex activities.