Component of the exocyst complex involved in the docking of exocytic vesicles with fusion sites on the plasma membrane during regulated or polarized secretion. Involved in polarized cell growth and organ morphogenesis. During cytokinesis, involved in secretory processes during cell plate initiation, cell plate maturation and formation of new primary cell wall. Participates in polarized pectin delivery required for the polarized development of the mucilage-producing volcano cells of the seed coat. The exocyst complex is composed of SEC3, SEC5, SEC6, SEC8, SEC10, EXO70A1 and EXO84B. During cytokinesis, localizes to the nascent cell plate and later to the cell plate insertion site and along the post-cytokinetic wall (PubMed:20870962). Shuttles from the cytoplasm to the exocyst-positive organelle (EXPO) in the presence of EXO70E2 (PubMed:24307681). Male gametophytic lethal due to defect in pollen germination and pollen tube growth. Belongs to the SEC8 family.