title: Plasma membrane inositol 1,4,5-trisphosphate receptor of lymphocytes: selective enrichment in sialic acid and unique binding specificity.
abstract: The inositol 1,4,5-trisphosphate receptor (IP3R) associated with plasma membranes of lymphocytes differs in terminal sugar content and binding specificity from the cerebellar receptor, which is localized to endoplasmic reticulum. Lectin column chromatography reveals that 30% of IP3R in the thymus contains sialic acid, reflecting a plasma membrane association, in contrast to 5% of cerebellar IP3R. IP3R in thymus and plasma membrane fractions of Jurkat lymphocytes differs from IP3R of Jurkat microsomes and cerebellum in inositol phosphate specificity. The plasma membrane IP3R has lower affinity for IP3 but higher affinity for inositol 1,3,4,5-tetrakisphosphate, which may reflect a unique regulation of calcium at the plasma membrane by inositol phosphates.
authors.affiliation: Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185.
authors.forename: A A
authors.initials: AA
authors.lastname: Khan
authors.forename: J P
authors.initials: JP
authors.lastname: Steiner
authors.forename: S H
authors.initials: SH
authors.lastname: Snyder
mesh_terms: D000818:Animals; D015220:Calcium Channels; D002462:Cell Membrane / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008214:Lymphocytes / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008861:Microsomes / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear; D011975:Receptors, Mitogen / Q000737:chemistry; D012794:Sialic Acids / Q000032:analysis; D013950:Thymus Gland / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D011975:Receptors, Mitogen; D012794:Sialic Acids; D015544:Inositol 1,4,5-Trisphosphate; D006493:Heparin