title: The ligand binding region of the sigma-1 receptor: studies utilizing photoaffinity probes, sphingosine and N-alkylamines.
abstract: The sigma-1 receptor is a 26 kDa endoplasmic reticulum resident membrane protein that has been shown to have chaperone activity in addition to its promiscuous binding to pharmacological agents. Ligand binding domain(s) of the sigma-1 receptor have been identified using the E. coli expressed and purified receptor protein and novel radioiodinated azido photoaffinity probes followed by proteolytic and chemical cleavage strategies. The outcome of these experiments indicates that the sigma-1 receptor ligand binding regions are formed primarily by juxtaposition of its second and third hydrophobic domains, regions where the protein shares considerable homology with the fungal enzyme, sterol isomerase that is essential for the biosynthesis of ergosterol. Data indicate that these hydrophobic steroid binding domain like (SBDL) regions on the sigma-1 receptor are likely to interact selectively with N-alkyl amines such as the endogenous sphingolipids and with synthetic N-alkylamines and N-aralkylamines derivatives. A proposed model for the sigma-1 receptor is presented.
authors.affiliation: Department of Neuroscience and the UW Eye Research Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA. aeruoho@wisc.edu
authors.forename: Arnold E
authors.initials: AE
authors.lastname: Ruoho
authors.forename: Uyen B
authors.initials: UB
authors.lastname: Chu
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Ramachandran
authors.forename: Dominique
authors.initials: D
authors.lastname: Fontanilla
authors.forename: Timur
authors.initials: T
authors.lastname: Mavlyutov
authors.forename: Abdol R
authors.initials: AR
authors.lastname: Hajipour
mesh_terms: D000473:Alkanes / Q000737:chemistry / Q000378:metabolism*; D000588:Amines / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D006801:Humans; D019920:Photoaffinity Labels / Q000737:chemistry / Q000378:metabolism*; D017480:Receptors, sigma / Q000737:chemistry* / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D000097605:Sigma-1 Receptor
chemical_list: D000473:Alkanes; D000588:Amines; D019920:Photoaffinity Labels; D017480:Receptors, sigma; D013110:Sphingosine; D000097605:Sigma-1 Receptor