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    Oh, what a difference an S makes: A thioribose analogue (cADPtR, see scheme) of cyclic ADP-ribose (cADPR) was synthesized that is stable and has structural and electrostatic features similar to those of cADPR. cADPtR is the first stable equivalent of cADPR that is as active as cADPR in various cellular systems, making it useful for investigating Ca2+ ion-release signaling pathways.
    Cyclic ADP-Ribose
    Second messenger system
    Ribose
    Citations (18)
    Human CD38 is a multifunctional ectoenzyme responsible for catalyzing the conversions from nicotinamide adenine dinucleotide (NAD) to cyclic ADP-ribose (cADPR) and from cADPR to ADP-ribose (ADPR). Both cADPR and ADPR are calcium messengers that can mobilize intracellular stores and activate influx as well. In this study, we determined three crystal structures of the human CD38 enzymatic domain complexed with cADPR at 1.5-A resolution, with its analog, cyclic GDP-ribose (cGDPR) (1.68 A) and with NGD (2.1 A) a substrate analog of NAD. The results indicate that the binding of cADPR or cGDPR to the active site induces structural rearrangements in the dipeptide Glu(146)-Asp(147) by as much as 2.7 A) providing the first direct evidence of a conformational change at the active site during catalysis. In addition, Glu(226) is shown to be critical not only in catalysis but also in positioning of cADPR at the catalytic site through strong hydrogen bonding interactions. Structural details obtained from these complexes provide a step-by-step description of the catalytic processes in the synthesis and hydrolysis of cADPR.
    Cyclic ADP-Ribose
    Second messenger system
    Citations (52)
    The concept advanced by Berridge and colleagues that intracellular Ca(2+)-stores can be mobilized in an agonist-dependent and messenger (IP(3))-mediated manner has put Ca(2+)-mobilization at the center stage of signal transduction mechanisms. During the late 1980s, we showed that Ca(2+)-stores can be mobilized by two other messengers unrelated to inositol trisphosphate (IP(3)) and identified them as cyclic ADP-ribose (cADPR), a novel cyclic nucleotide from NAD, and nicotinic acid adenine dinucleotide phosphate (NAADP), a linear metabolite of NADP. Their messenger functions have now been documented in a wide range of systems spanning three biological kingdoms. Accumulated evidence indicates that the target of cADPR is the ryanodine receptor in the sarco/endoplasmic reticulum, while that of NAADP is the two pore channel in endolysosomes.As cADPR and NAADP are structurally and functionally distinct, it is remarkable that they are synthesized by the same enzyme. They are thus fraternal twin messengers. We first identified the Aplysia ADP-ribosyl cyclase as one such enzyme and, through homology, found its mammalian homolog, CD38. Gene knockout in mice confirms the important roles of CD38 in diverse physiological functions from insulin secretion, susceptibility to bacterial infection, to social behavior of mice through modulating neuronal oxytocin secretion. We have elucidated the catalytic mechanisms of the Aplysia cyclase and CD38 to atomic resolution by crystallography and site-directed mutagenesis. This article gives a historical account of the cADPR/NAADP/CD38-signaling pathway and describes current efforts in elucidating the structure and function of its components.
    Cyclic ADP-Ribose
    Second messenger system
    Calcium Signaling
    Ribose
    Citations (59)
    Analogues of the potent Ca(2+) releasing second messenger cyclic ADP-ribose (cADPR) with a 1,2,3-triazole pyrophosphate bioisostere were synthesised by click-mediated macrocyclisation. The ability to activate Ca(2+) release was surprisingly retained, and hydrolysis of cADPR by CD38 could also be inhibited, illustrating the potential of this approach to design drug-like signalling pathway modulators.
    Cyclic ADP-Ribose
    Second messenger system
    Bioisostere
    Ribose
    Citations (25)
    Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) are two Ca(2+) messengers derived from NAD and NADP, respectively. Although NAADP is a linear molecule, structurally distinct from the cyclic cADPR, it is synthesized by similar enzymes, ADP-ribosyl cyclase and its homolog, CD38. The crystal structure of the cyclase has been solved and its active site identified. These two novel nucleotides have now been shown to be involved in a wide range of cellular functions including: cell cycle regulation in Euglena, a protist; gene expression in plants; and in animal systems, from fertilization to neurotransmitter release and long-term depression in brain. A battery of pharmacological reagents have been developed, providing valuable tools for elucidating the physiological functions of these two novel Ca(2+) messengers. This article reviews these recent results and explores the implications of the existence of multiple Ca(2+) messengers and Ca(2+) stores in cells.
    Second messenger system
    Cyclic ADP-Ribose
    It is generally believed that multiple Ca2+ stores are present in cells, a notion that has now been made substantive by the discovery of multiple Ca2+ mobilizing messengers. Cyclic ADP-ribose (cADPR) and nicotinic acid dinucleotide phosphate (NAADP) are two such messengers that are derived from NAD and NADP, respectively. A wide variety of cells, from plants to mammals, including human, have been shown to be responsive to these two novel Ca2+ messengers. Not only are their structures and mechanisms of action different, their targeted Ca2+ stores are also distinct and separable. This article explores the implications of the multiplicity of Ca2+ stores in cellular signaling. Special emphasis will be put on the recent progress in the understanding of the physiological functions of NAADP.
    Cyclic ADP-Ribose
    Second messenger system
    Citations (119)
    Second messenger system
    Moiety
    Cyclic ADP-Ribose
    Citations (12)
    Cyclic ADP-ribose(cADPR) is a Ca2+ mobilizing second messenger in various types of cell,tissue and organism.cADPR regulates the release of Ca2+ depending on the gating properties of ryanodine receptors(RyRs),which is transmembrane shuttling of the substrate coenzyme Ⅰ(NAD+) and the product cADPR,or ligand-induced internalization of CD38.This review summarizes mechanisms of cADPR synthesis and its regulation on intracellular Ca2+ release.
    Cyclic ADP-Ribose
    Second messenger system
    Internalization
    Citations (0)