Component of the exocyst complex involved in the docking of exocytic vesicles with fusion sites on the plasma membrane. Involved in regulation of synaptic microtubule formation, and also regulation of synaptic growth and glutamate receptor trafficking. Does not appear to be required for basal neurotransmission. The exocyst complex is composed of Sec3/Exoc1, Sec5/Exoc2, Sec6/Exoc3, Sec8/Exoc4, Sec10/Exoc5, Sec15/Exoc6, exo70/Exoc7 and Exo84/Exoc8. Abundant in the embryonic and larval glutamatergic neuromuscular junctions (NMJs), pre and postsynaptically. Expressed both maternally and zygotically. Flies exhibit defects in development of glutamatergic neuromuscular junctions (NMJs): increase in synaptic microtubule density. Belongs to the SEC8 family.