Ectocellular CD38‐catalyzed synthesis and intracellular Ca2+‐signalling activity of cyclic ADP‐ribose in T‐lymphocytes are not functionally related

FEBS Letters

Heyer, Petra¹  da Silva, Cristina P¹  Malavasi, Fabio²  Guse, Andreas H¹  Schweitzer, Katrin¹  Mayr, Georg W¹ 

[1] University of Hamburg, Institute of Physiological Chemistry, Department of Enzyme Chemistry, Grindelallee 117, 20146 Hamburg, Germany;Institute of Biology and Genetics, University of Ancona, Ancona, Italy

关键词: Cyclic adenosine diphosphate ribose;    CD38;    ADP-ribosyl cyclase;    Intracellular calcium;    NAD+;    Human T-lymphocyte;    T-cell receptor;    ADPR;    adenosine diphosphate ribose;    cADPR;    cyclic adenosine diphosphate ribose;    cGDPR;    cyclic guanosine diphosphate ribose;    [Ca2+]i;    intracellular calcium concentration;    FACS;    fluorescence activated cell sorter;    HPLC;    high performance liquid chromatography;    IB4;    agonistic monoclonal antibody against CD38;    LPA;    lysophosphatidic acid;    NGD+;    nicotinamide guanine dinucleotide;    SPH;    d-erythro-sphingosine;   

DOI  :  10.1016/S0014-5793(98)01396-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cyclic ADP-ribose (cADPR) is a natural metabolite of β-NAD⁺ with a potent Ca²⁺-mobilizing activity in different cell types, including T-lymphocytes. We investigated (i) whether stimulation of T-lymphocytes with different agonists affects the intracellular concentration of cADPR, and (ii) whether the lymphocyte antigen CD38, through its ectocellular ADP-ribosyl cyclase and cADPR-hydrolase enzymatic activities, can account for the regulation of the intracellular levels of cADPR and the Ca²⁺-mobilizing effects of this nucleotide in Jurkat and HPB.ALL T-lymphocytes. The anti-CD3 antibody OKT3, the sphingolipid sphingosine and lysophosphatidic acid induced an increase in intracellular cADPR with concomitant increases in the intracellular Ca²⁺ concentration ([Ca²⁺]_i). In contrast, activation of an ectocellular ADP-ribosyl cyclase by preincubation of cells with β-NAD⁺ led to a dose-dependent increase in cADPR, but no changes in [Ca²⁺]_i were observed. However, extensive washing of the cells following preincubation with NAD⁺ demonstrated that the increases in cADPR were not intracellular but due to cell surface-associated nucleotide. Accordingly, measurements of ADP-ribosyl cyclase activity in intact T-cells showed ectocellular synthesis of cADPR, but no evidence was obtained for a shift of this activity into the cells which could account for intracellular accumulation of cADPR. Taken together, the results indicate no direct involvement of the ADP-ribosyl cyclase activity of CD38 on the regulation of the cADPR-mediated intracellular Ca²⁺-signalling in T-lymphocytes.

【 授权许可】

Unknown