Synthesis of NAADP and cADPR in mitochondria. Arch Biochem Biophys 1999 Nov 15;371(2):317-25
Date
11/05/1999Pubmed ID
10545220DOI
10.1006/abbi.1999.1463Scopus ID
2-s2.0-0033571480 (requires institutional sign-in at Scopus site) 42 CitationsAbstract
Here we investigated whether cADPR and NAADP are synthesized in mitochondria. We found that ADPR-cyclase activity is present in mitochondria. In addition, we describe for the first time synthesis of NAADP in this intracellular organelle. ADPR-cyclase activities (V(MAX)) and NAADP synthesis in mitochondria were about 4-fold lower than that in plasma membranes. Otherwise, ADPR-cyclases in mitochondria and in plasma membranes have similar catalytic properties in terms of apparent K(m) for the substrate NGD and K(i) values for inhibition by dithiotreitol, beta-NAD, and nicotinamide. ADPR-cyclase in plasma membranes and to a lesser degree mitochondrial enzyme, was inhibited by Zn(2+) and Cu(2+); ADPR-cyclase from mitochondria was more stable upon thermal inactivation. CD38 antigen, determined by Western blot, was well-expressed in plasma membranes but was far less so (17-fold less) in mitochondria. The major difference between ADPR-cyclase activity in mitochondria and plasma membranes is that mitochondrial cyclase activity was increased by incubation with nonionic detergents. Conversely, the incubation with phosphatidylinositol-specific phosphodiesterase C (PI-PLC) released ADPR-cyclase activity from plasma membranes, but not from mitochondria. We conclude that ADPR-cyclase in mitochondria and in plasma membranes are both multifunctional enzymes with similar catalytic properties; however, the two ADPR-cyclases differ in the mode of anchoring to the membrane: by glycosylphosphoinositol anchor in plasma membranes and by hydrophobic interactions in mitochondria. In addition, synthesis of NAADP can also be found in intracellular organelles via mitochondria. We propose that independent mitochondrial cADPR and NAADP systems may have an intracrine signaling function that is not dependent on direct input by extracellular hormonal stimuli, but rather responds to changes of intermediary cellular metabolism.
Author List
Liang M, Chini EN, Cheng J, Dousa TPMESH terms used to index this publication - Major topics in bold
ADP-ribosyl CyclaseADP-ribosyl Cyclase 1
Adenosine Diphosphate Ribose
Animals
Antigens, CD
Antigens, Differentiation
Cell Compartmentation
Cell Membrane
Cyclic ADP-Ribose
Dithiothreitol
Glycosylphosphatidylinositols
Guanine Nucleotides
Isoenzymes
Membrane Glycoproteins
Mitochondria, Liver
Multienzyme Complexes
NAD
NAD+ Nucleosidase
NADP
Niacinamide
Phosphatidylinositol Diacylglycerol-Lyase
Phosphoinositide Phospholipase C
Rats
Rats, Sprague-Dawley
Type C Phospholipases