Subtopic Deep Dive

← Calcium signaling and nucleotide metabolism

Cyclic ADP-Ribose in Calcium Signaling
Research Guide

What is Cyclic ADP-Ribose in Calcium Signaling?

Cyclic ADP-ribose (cADPR) is a nucleotide second messenger synthesized from NAD+ by ADP-ribosyl cyclases like CD38 that sensitizes ryanodine receptors (RyRs) to trigger calcium release from endoplasmic reticulum stores.

cADPR mediates calcium-induced calcium release (CICR) in sea urchin eggs and mammalian cells via RyR activation (Davis et al., 1991, 624 citations). CD38 generates cADPR, linking NAD+ metabolism to calcium signaling in excitable and non-excitable cells (Malavasi et al., 2008, 830 citations). Over 10 papers in the provided list detail its synthesis, gating of TRPM2 channels by ADP-ribose, and cross-talk with NAADP pathways.

Curated Papers

Key Challenges

Why It Matters

cADPR regulates excitability in neurons, muscle cells, and immune cells by amplifying calcium signals from ER stores, with therapeutic potential in NAD+ boosting for neurodegeneration (Houtkooper et al., 2010). CD38 inhibitors modulate cADPR levels to treat inflammation and cancer, as CD38 expression predicts prognosis in chronic lymphocytic leukemia (Hamblin et al., 2002). ADP-ribose activates TRPM2 channels for calcium influx, influencing oxidative stress responses (Perraud et al., 2001). These mechanisms connect nucleotide metabolism to calcium-dependent pathologies like diabetes and heart disease (Xie et al., 2020).

Key Research Challenges

Quantifying cADPR levels

Endogenous cADPR concentrations are picomolar, complicating detection amid NAD+ excess (Malavasi et al., 2008). Assays lack specificity due to cyclic structure stability (Lee et al., 1991 via Davis). Recent NAD+ studies highlight need for isoform-specific cyclases (Pollak et al., 2007).

RyR sensitization mechanism

cADPR binds RyR but exact conformational changes remain unresolved (Davis et al., 1991). Cross-talk with NAADP/TPC pathways confounds isolation (Calcraft et al., 2009). Structural studies lag behind NAADP field.

Physiological oscillators

cADPR/CD38 rhythms drive calcium oscillations in T-cells and oocytes, but coupling to metabolism unclear (Malavasi et al., 2008). Models fail to predict frequency under stress (Xie et al., 2020). Genetic redundancy with CD157 complicates knockouts.

Essential Papers

NAD+ metabolism: pathophysiologic mechanisms and therapeutic potential

Na Xie, Lu Zhang, Wei Gao et al. · 2020 · Signal Transduction and Targeted Therapy · 897 citations

Abstract Nicotinamide adenine dinucleotide (NAD + ) and its metabolites function as critical regulators to maintain physiologic processes, enabling the plastic cells to adapt to environmental chang...

ADP-ribose gating of the calcium-permeable LTRPC2 channel revealed by Nudix motif homology

Anne‐Laure Perraud, Andrea Fleig, Christopher Dunn et al. · 2001 · Nature · 888 citations

The Secret Life of NAD+: An Old Metabolite Controlling New Metabolic Signaling Pathways

Riekelt H. Houtkooper, Carles Cantó, Ronald J. A. Wanders et al. · 2010 · Endocrine Reviews · 863 citations

A century after the identification of a coenzymatic activity for NAD+, NAD+ metabolism has come into the spotlight again due to the potential therapeutic relevance of a set of enzymes whose activit...

Evolution and Function of the ADP Ribosyl Cyclase/CD38 Gene Family in Physiology and Pathology

Fabio Malavasi, Silvia Deaglio, Ada Funaro et al. · 2008 · Physiological Reviews · 830 citations

The membrane proteins CD38 and CD157 belong to an evolutionarily conserved family of enzymes that play crucial roles in human physiology. Expressed in distinct patterns in most tissues, CD38 (and C...

NAADP mobilizes calcium from acidic organelles through two-pore channels

Peter Calcraft, Margarida Ruas, Zui Pan et al. · 2009 · Nature · 738 citations

The power to reduce: pyridine nucleotides – small molecules with a multitude of functions

Nadine Pollak, Christian Dölle, Mathias Ziegler · 2007 · Biochemical Journal · 707 citations

The pyridine nucleotides NAD and NADP play vital roles in metabolic conversions as signal transducers and in cellular defence systems. Both coenzymes participate as electron carriers in energy tran...

Nicotinamide riboside is uniquely and orally bioavailable in mice and humans

Samuel A.J. Trammell, Mark S. Schmidt, Benjamin J. Weidemann et al. · 2016 · Nature Communications · 662 citations

Reading Guide

Foundational Papers

Start with Davis et al. (1991, Science, 624 cites) for CICR discovery in homogenates; Perraud et al. (2001, Nature, 888 cites) for ADP-ribose channel gating; Malavasi et al. (2008, Physiological Reviews, 830 cites) for CD38 synthesis overview.

Recent Advances

Xie et al. (2020) for NAD+ pathophysiology; Houtkooper et al. (2010) for signaling integration; Trammell et al. (2016) for precursor bioavailability.

Core Methods

CICR assays in homogenates (Davis 1991); Nudix homology for channel gating (Perraud 2001); cyclase kinetics via HPLC (Malavasi 2008); NAADP cross-talk via two-pore channels (Calcraft 2009).

How PapersFlow Helps You Research Cyclic ADP-Ribose in Calcium Signaling

Discover & Search

Research Agent uses searchPapers('cyclic ADP-ribose RyR calcium signaling') to retrieve Davis et al. (1991), then citationGraph reveals 888-citation Perraud et al. (2001) on ADP-ribose/TRPM2, and findSimilarPapers expands to Malavasi et al. (2008) CD38 family.

Analyze & Verify

Analysis Agent applies readPaperContent on Malavasi et al. (2008) to extract CD38 kinetics, verifyResponse with CoVe cross-checks cADPR-RyR claims against Davis et al. (1991), and runPythonAnalysis simulates CICR dose-response curves using NumPy for GRADE A verification of oscillator models.

Synthesize & Write

Synthesis Agent detects gaps in RyR structural data across papers, flags contradictions between TRPM2 gating (Perraud et al., 2001) and NAADP paths (Calcraft et al., 2009); Writing Agent uses latexEditText for figure legends, latexSyncCitations for 10+ refs, latexCompile for manuscript, and exportMermaid for cADPR synthesis pathway diagrams.

Use Cases

"Model cADPR-induced calcium oscillations from sea urchin egg data"

Research Agent → searchPapers → Analysis Agent → runPythonAnalysis (NumPy ODE solver on Davis et al. 1991 transients) → matplotlib plots of CICR frequency vs [cADPR].

"Draft review section on CD38-cADPR in immune calcium signaling"

Synthesis Agent → gap detection on Malavasi et al. (2008) → Writing Agent → latexEditText → latexSyncCitations (Hamblin 2002) → latexCompile → PDF with cited equations.

"Find code for TRPM2/ADP-ribose simulations linked to papers"

Research Agent → paperExtractUrls (Perraud 2001) → Code Discovery → paperFindGithubRepo → githubRepoInspect → pandas analysis of simulation outputs.

Automated Workflows

Deep Research workflow scans 50+ OpenAlex papers on 'cADPR RyR', chains citationGraph → readPaperContent → GRADE report ranking Malavasi (830 cites) highest. DeepScan applies 7-step CoVe to verify CD38 synthesis rates from Pollak et al. (2007), outputting verified kinetics table. Theorizer generates hypotheses linking cADPR oscillators to NAD+ decline in aging (Xie et al., 2020).

Try Doxa for Cyclic ADP-Ribose in Calcium Signaling Research

Frequently Asked Questions

What defines cyclic ADP-ribose in calcium signaling?

cADPR is NAD+-derived cyclic nucleotide that binds RyRs to amplify ER calcium release, first shown in sea urchin eggs (Davis et al., 1991).

How is cADPR synthesized?

CD38 and CD157 catalyze NAD+ to cADPR via ADP-ribosyl cyclase activity, expressed in immune cells and neurons (Malavasi et al., 2008).

What are key papers?

Foundational: Perraud et al. (2001, 888 cites) on ADP-ribose/TRPM2; Malavasi et al. (2008, 830 cites) on CD38 family; recent: Xie et al. (2020, 897 cites) on NAD+ therapeutics.