iGluSnFR(A184L) is a genetically encoded fluorescent sensor designed for in vivo detection of glutamate release in neurological systems. It is a fusion protein composed of an N-terminal IgG kappa secretion tag, the glutamate-binding protein encoded by the Escherichia coli gltI gene, with a circularly permuted form of GFP (cpGFP146) inserted (with linkers either side) between residues 253 and 254, a Tag:MYC tag and a C-terminal transmembrane domain from PDGFR (which anchors the protein to the membrane and displays it on the extracellular side) (PMID:23314171). iGluSnFR(A184L) contains an L amino acid residue at position 184 in the gltI sequence; variants at this residue differ in their affinity to glutamate, from tightest to weakest: A184A > A184S > A184V > A184L (PMID:30377363, FBrf0229856). For a comparison of the iGluSnFR(A184L) sensor with other iGluSnFR variants, see PMID:30377363.