QUAS regulatory sequences drive expression of 'pre-mGRASP' tagged at the C-terminal end with 2xTag:HA followed by sequence encoding the intracellular tail of Lar. pre-mGRASP (PMID:22138823) is composed of an N-terminal signal peptide, the spGFP11 split fluorescent protein fragment, the extracellular and transmembrane domains of the human CD4 gene and an intracellular domain that targets the protein to presynaptic sites (Tag:TS(rNrxn1-β)).