NAD+‐dependent internalization of the transmembrane glycoprotein CD38 in human Namalwa B cells

FEBS Letters

Tacchetti, Carlo¹  Zocchi, Elena²  Guida, Lucrezia²  Franco, Luisa²  Piccini, Daniele¹  De Flora, Antonio² 

[1] Institute of Anatomy, University of Genoa, Via T. de Toni 14, 16132 Genoa, Italy;Institute of Biochemistry, University of Genoa, and Advanced Biotechnology Center, Viale Benedetto XV/1, 16132 Genoa, Italy

关键词: CD38;    NAD+;    GSH;    ADP-ribosyl cyclase;    Endocytosis;    Ectoenzyme;    cADPR;    cyclic ADP-ribose;    ADPR;    ADP-ribose;    BSA;    bovine serum albumin;    NGD+;    nicotinamide guanine dinucleotide;    cGDPR;    cyclic GDP-ribose;    RIA;    radioimmunoassay;   

DOI  :  10.1016/0014-5793(96)01125-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

CD38 is a transmembrane glycoprotein involved as an orphan receptor in many physiological processes of lymphocytes. It is also a bifunctional enzyme that catalyzes at its ectocellular domain the synthesis from NAD⁺ (cyclase) and the hydrolysis (hydrolase) of the calcium-mobilizing metabolite cyclic ADP-ribose (cADPR). A still unexplained paradox concerns the relationship between ectocellular localization of CD38 and intracellular calcium-releasing activity of its intermediate product cADPR. Incubation of CD38⁺ human Namalwa B cells with external NAD⁺ elicited extensive membrane down-regulation of CD38 and its internalization in non-clathrin-coated vesicles. Since the internalized CD38 was demonstrated to be enzymatically active, this NAD⁺-dependent process is a hitherto unrecognized means for shifting cADPR metabolism from the cell surface to the intracellular environment.

【 授权许可】

Unknown