Click
here to close Hello! We notice that
you are using Internet Explorer, which is not supported by Echinobase
and may cause the site to display incorrectly. We suggest using a
current version of Chrome,
FireFox,
or Safari.
Anal Biochem
2007 Dec 01;3711:26-36. doi: 10.1016/j.ab.2007.08.030.
Show Gene links
Show Anatomy links
Refinement of a radioreceptor binding assay for nicotinic acid adenine dinucleotide phosphate.
Lewis AM
,
Masgrau R
,
Vasudevan SR
,
Yamasaki M
,
O'Neill JS
,
Garnham C
,
James K
,
Macdonald A
,
Ziegler M
,
Galione A
,
Churchill GC
.
???displayArticle.abstract???
The measurement of changes in nicotinic acid adenine dinucleotide phosphate (NAADP) levels in cells has been, and remains, key to the investigation of the functions of NAADP as a Ca2+ -releasing second messenger. Here we provide details of how to isolate NAADP from cells by extraction with perchloric acid and then measure the NAADP using a radioreceptor assay. We demonstrate that NAADP is neither generated nor broken down during sample processing conditions and that radioreceptor assay is highly selective for the detection of NAADP under cell extract conditions. Furthermore, a number of improvements, such as solid-state detection of the radioactivity, are incorporated to enhance the safety of the procedure. Finally, we have developed a new method to prevent the endogenous metabolism of NAADP by chelating Ca2+ with bis-(o-aminophenoxy)ethane-N,N,N'',N''-tetraacetic acid (BAPTA), thereby reducing the difficulty of catching a small transient rise in NAADP levels. In summary, we have refined and improved a method for measuring NAADP levels and presented it in a manner accessible to a wide range of laboratories. It is expected that this will enhance research in the NAADP field.
Fig. 1. (A) Schematic diagram of the acid extraction process for NAADP. Sperm or eggs are harvested from L. pictus, or cells are prepared from male CD1 mouse pancreas. Agonist is incubated with the cell preparation, and then HClO4 is added to stop the reaction at the required time point. The sample is then sonicated to disrupt the cells and is centrifuged to pellet the protein for subsequent assay. The supernatant is neutralized with an equal volume of 2 M KHCO3, or other bases where indicated, in preparation for analysis using the radioreceptor binding assay. (B) Schematic diagram of the NAADP radioreceptor binding assay. First, known concentrations of NAADP (blue boxes), or cell extracts, are added, followed by sea urchin egg homogenate (pale blue shapes) in intracellular medium and a 10-min incubation period. NAADP binds irreversibly to the receptors in the homogenate. [32P]NAADP (red boxes) is then added. This binds to the remaining available receptor sites. Bound NAADP is separated from the mixture by filtration, and the radioactivity is determined. Sample NAADP concentrations may be determined from the standard curve. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 2. Stability of nucleotides during the acid extraction procedure. (A) Schematic showing the procedure. NAADP, NADP, or NADPH (1 mM) was incubated for 6 h in the solutions indicated. Samples were then neutralized by the addition of Hepes acid for basic samples, or Tris base for acidic samples, and were analyzed by HPLC. HPLC traces show the stability of NAADP, NADP, and NADPH in Hepes (pH 7.2) (B), HClO4 (pH 0.88) (C), HClO4 neutralized with KHCO3 (pH 8.6) (D), KHCO3 (pH 9.1) (E), and K2CO3 (pH 11) (F). HPLC traces are scaled to a common peak height for comparison (maximum 20% scaling). Note that NADP is stable except at pH 11, when a number of products result; in particular, NAADP is generated, and this would interfere with correct determination of NAADP levels from a cell extract. NADPH is stable only at pH 7.2, but NADP is the principal breakdown product; NAADP is not produced under the conditions tested. a.u., arbitrary unit.
Fig. 3. Synthesis of [32P]NAADP. (A) HPLC traces of the test reactions using unlabeled compounds. First, NAD is converted to NADP using NAD kinase. Second, NADP is converted to NAADP using ADP-ribosyl cyclase. (B) Separation of the [32P]NAADP from the reaction mixture. Detection of unlabeled compounds is performed by UV detection at 254 nm. 32P-labeled compounds are detected as counts per minute (cpm) using an in-line Geiger counter.
Fig. 4. Measurement of NAADP levels in pancreatic acinar cell samples. (A) Schematic diagram showing the preparation of pancreatic acinar cell samples. These samples were then diluted for use in the assay. (B) A competitive displacement curve was generated using standard concentrations of NAADP (black filled circles). Dilutions of the pancreatic acinar cell sample were determined from this curve and are shown on the trace (red triangles). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 5. Detection of changes in NAADP concentration under cell extract conditions. The displacement curve was generated from known NAADP concentrations (blue squares). The difference between known NAADP concentrations spiked into rat brain extract (prepared as described in text) is correctly detected (red circles). Error bars represent standard errors of the mean (n = 3). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 6. Improvement of NAADP detection in cell extract samples. The green trace shows standards made in intracellular medium (Glu-IM), the blue trace shows standards in “acid-extracted” intracellular medium, and the red trace shows standards in intracellular medium supplemented with 1 M potassium acetate. Error bars represent standard errors of the mean (n = 3). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 7. Detection of radioactivity using storage phosphor screens and a Typhoon scanner. (A) Comparison of radioactivity determined by the Typhoon scanner image versus counts per minute (cpm) detected using Cerenkov scintillation counting. (B) Image produced for a standard NAADP displacement curve using the Typhoon scanner . (C) Comparison of standard curves with radioactivity detected using scintillation counting (red symbols and line) and the Typhoon scanner (blue symbols and line). Error bars represent standard errors of the mean (n = 3). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Fig. 8. BAPTA-AM, a cell-permeant form of the Ca2+ chelator BAPTA, prevents NAADP metabolism and, hence, facilitates NAADP measurements in pancreatic acinar cells. The red trace shows cells preincubated with 20 μM BAPTA-AM, followed by the addition of control buffer and incubations for the various times. The blue trace shows cells that were preincubated with BAPTA-AM, followed by addition of 100 pM CCK for the times indicated. Error bars represent standard errors of the mean (n = 3). The inset (green trace) shows an initial peak in NAADP levels in response to CCK in the absence of BAPTA. This response is very transient and, hence, difficult to detect. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)
Aarhus,
ADP-ribosyl cyclase and CD38 catalyze the synthesis of a calcium-mobilizing metabolite from NADP.
1995, Pubmed
Aarhus,
ADP-ribosyl cyclase and CD38 catalyze the synthesis of a calcium-mobilizing metabolite from NADP.
1995,
Pubmed
Aarhus,
Activation and inactivation of Ca2+ release by NAADP+.
1996,
Pubmed
,
Echinobase
Berridge,
The versatility and universality of calcium signalling.
2000,
Pubmed
Berridge,
Metabolism of the novel Ca2+-mobilizing messenger nicotinic acid-adenine dinucleotide phosphate via a 2'-specific Ca2+-dependent phosphatase.
2002,
Pubmed
Billington,
Characterization of NAADP(+) binding in sea urchin eggs.
2000,
Pubmed
,
Echinobase
Billington,
Nicotinic acid adenine dinucleotide phosphate (NAADP) is present at micromolar concentrations in sea urchin spermatozoa.
2002,
Pubmed
,
Echinobase
Bredt,
A simple, sensitive, and specific radioreceptor assay for inositol 1,4,5-trisphosphate in biological tissues.
1989,
Pubmed
Cancela,
Two different but converging messenger pathways to intracellular Ca(2+) release: the roles of nicotinic acid adenine dinucleotide phosphate, cyclic ADP-ribose and inositol trisphosphate.
2000,
Pubmed
Churamani,
Determination of cellular nicotinic acid-adenine dinucleotide phosphate (NAADP) levels.
2004,
Pubmed
,
Echinobase
Churchill,
NAADP mobilizes Ca(2+) from reserve granules, lysosome-related organelles, in sea urchin eggs.
2002,
Pubmed
,
Echinobase
Churchill,
Sperm deliver a new second messenger: NAADP.
2003,
Pubmed
,
Echinobase
Clapper,
Pyridine nucleotide metabolites stimulate calcium release from sea urchin egg microsomes desensitized to inositol trisphosphate.
1987,
Pubmed
,
Echinobase
Dargie,
Comparison of Ca2+ mobilizing activities of cyclic ADP-ribose and inositol trisphosphate.
1990,
Pubmed
,
Echinobase
Dawis,
Adenosine triphosphate utilization rates and metabolic pool sizes in intact cells measured by transfer of 18O from water.
1989,
Pubmed
Gasser,
Second messenger function of nicotinic acid adenine dinucleotide phosphate revealed by an improved enzymatic cycling assay.
2006,
Pubmed
Graeff,
A novel cycling assay for nicotinic acid-adenine dinucleotide phosphate with nanomolar sensitivity.
2002,
Pubmed
Kinnear,
Lysosome-sarcoplasmic reticulum junctions. A trigger zone for calcium signaling by nicotinic acid adenine dinucleotide phosphate and endothelin-1.
2004,
Pubmed
Lee,
A derivative of NADP mobilizes calcium stores insensitive to inositol trisphosphate and cyclic ADP-ribose.
1995,
Pubmed
,
Echinobase
Lerner,
Structural and functional characterization of human NAD kinase.
2001,
Pubmed
Malaisse,
Cyclic ADP-ribose measurements in rat pancreatic islets.
1997,
Pubmed
Masgrau,
NAADP: a new second messenger for glucose-induced Ca2+ responses in clonal pancreatic beta cells.
2003,
Pubmed
Navazio,
Calcium release from the endoplasmic reticulum of higher plants elicited by the NADP metabolite nicotinic acid adenine dinucleotide phosphate.
2000,
Pubmed
,
Echinobase
Patel,
Unique kinetics of nicotinic acid-adenine dinucleotide phosphate (NAADP) binding enhance the sensitivity of NAADP receptors for their ligand.
2000,
Pubmed
,
Echinobase
Rowley,
Cholecystokinin-induced formation of inositol phosphates in pancreatic acini.
1990,
Pubmed
Takahashi,
Accumulation of cyclic ADP-ribose measured by a specific radioimmunoassay in differentiated human leukemic HL-60 cells with all-trans-retinoic acid.
1995,
Pubmed
Taylor,
Calcium signalling: IP3 rises again...and again.
2001,
Pubmed
Walseth,
Determination of endogenous levels of cyclic ADP-ribose in rat tissues.
1991,
Pubmed
,
Echinobase
Yamaguchi,
An enzymatic cycling assay for nicotinic acid adenine dinucleotide phosphate using NAD synthetase.
2007,
Pubmed
Yamasaki,
Organelle selection determines agonist-specific Ca2+ signals in pancreatic acinar and beta cells.
2004,
Pubmed
Yamasaki,
Role of NAADP and cADPR in the induction and maintenance of agonist-evoked Ca2+ spiking in mouse pancreatic acinar cells.
2005,
Pubmed
,
Echinobase
da Silva,
Quantification of intracellular levels of cyclic ADP-ribose by high-performance liquid chromatography.
1998,
Pubmed