A protein complex peripherally associated with the plasma membrane that determines where vesicles dock and fuse. At least eight complex components are conserved between yeast and mammals. [ http://www.ncbi.nlm.nih.gov/pubmed/27243008 http://www.ncbi.nlm.nih.gov/pubmed/9700152 http://www.ncbi.nlm.nih.gov/pubmed/15292201 ]