Structure of the σ1 Receptor and its Ligand Binding Site

The exact 3D structure of the enigmatic σ1 receptor is unknown, as the crystal structure of this protein has not been solved so far. Many efforts have been devoted to unveil the structure of the sigma1 receptor and, specifically, its binding site, which include photoaffinity labeling, site directed mutagenesis, and homology modeling. Aim of the present communication is to give a short overview of all results which contribute to the current knowledge of the σ1 receptor and its ligand binding site.