title: Complex gangliosides as cell surface inhibitors for the ecto-NAD+ glycohydrolase of CD38.
abstract: Leukocyte cell surface antigen CD38 is a single-transmembrane protein whose extracellular domain has catalytic activity for NAD(+) glycohydrolase (NADase). We previously reported that b-series gangliosides inhibit the NADase activity of the extracellular domain of CD38 expressed as a fusion protein [Hara-Yokoyama, M., Kukimoto, I., Nishina, H., Kontani, K., Hirabayashi, Y., Irie, F., Sugiya, H., Furuyama, S., and Katada, T. (1996) J. Biol. Chem. 271, 12951-12955]. In the present study, we examined the effect of exogenous gangliosides on the NADase activity of CD38 on the surface of retinoic acid-treated human leukemic HL60 cells and CD38-transfected THP-1 cells. After incubation of the cells with G(T1b), inhibition of NADase activity was observed. The time course of inhibition was slower than that of the incorporation of G(T1b) into the cells, suggesting that incorporation into the cell membranes is a prerequisite for inhibition. Inhibition occurred efficiently when G(T1b) and CD38 were present on the same cells (cis interaction) rather than on different cells (trans interaction). Although gangliosides may affect localization of cell surface proteins, indirect immunofluorescence intensity due to CD38 was not affected after G(T1b) treatment. Comparison of the effect of G(T1b) and G(D1a) indicates that the tandem sialic acid residues linked to the internal galactose residue of the gangliotetraose core are crucial to the inhibition. These results suggest a novel role of complex gangliosides for the first time as cell surface inhibitors of CD38 through specific and cis interaction between the oligosaccharide moiety and the extracellular domain.
authors.affiliation: Department of Physiology, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakae-cho Nishi, Matsudo, Chiba 271-8587, Japan. yokoyama@mascat.nihon-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Hara-Yokoyama
authors.forename: Y
authors.initials: Y
authors.lastname: Nagatsuka
authors.forename: O
authors.initials: O
authors.lastname: Katsumata
authors.forename: F
authors.initials: F
authors.lastname: Irie
authors.forename: K
authors.initials: K
authors.lastname: Kontani
authors.forename: S
authors.initials: S
authors.lastname: Hoshino
authors.forename: T
authors.initials: T
authors.lastname: Katada
authors.forename: Y
authors.initials: Y
authors.lastname: Ono
authors.forename: J
authors.initials: J
authors.lastname: Fujita-Yoshigaki
authors.forename: H
authors.initials: H
authors.lastname: Sugiya
authors.forename: S
authors.initials: S
authors.lastname: Furuyama
authors.forename: Y
authors.initials: Y
authors.lastname: Hirabayashi
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD / Q000378:metabolism; D000943:Antigens, Differentiation / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D005110:Extracellular Space / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005434:Flow Cytometry; D005732:Gangliosides / Q000378:metabolism / Q000494:pharmacology* / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D006868:Hydrolysis; D008562:Membrane Glycoproteins; D009699:N-Glycosyl Hydrolases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D004791:Enzyme Inhibitors; D005732:Gangliosides; D008562:Membrane Glycoproteins; D009844:Oligosaccharides; C084317:GQ1balpha ganglioside; C016481:trisialoganglioside GT1; C039129:GQ1b ganglioside; D009699:N-Glycosyl Hydrolases; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1