Component of the exocyst complex involved in the docking of exocytic vesicles with fusion sites on the plasma membrane. The exocyst complex is composed of Sec3/Exoc1, Sec5/Exoc2, Sec6/Exoc3, Sec8/Exoc4, Sec10/Exoc5, Sec15/Exoc6, Exo70/Exoc7 and Exo84/Exoc8. Belongs to the SEC6 family.