Endogenous ADP-ribose enables calcium-regulated cation currents through TRPM2 channels in neutrophil granulocytes.

ABSTRACT: TRPM2 (transient receptor potential melastatin 2) is a Ca2+-permeable cation channel gated by ADPR (ADP-ribose) from the cytosolic side. To test whether endogenous concentrations of intracellular ADPR are sufficient for TRPM2 gating in neutrophil granulocytes, we devised an HPLC method to determine ADPR contents in HClO4 cell extracts. The reversed-phase ion-pair HPLC method with an Mg2+-containing isocratic eluent allows baseline resolution of one ADPR peak. Intracellular ADPR concentrations were approx. 5 muM in granulocytes and not significantly altered by stimulation with the chemoattractant peptide fMLP (N-formylmethionyl-leucylphenylalanine). We furthermore determined intracellular concentrations of cADPR (cyclic ADPR) with a cyclase assay involving enzymatic conversion of cADPR into

SUBMITTER: Heiner I 

PROVIDER: S-EPMC1550310 | biostudies-literature | 2006 Sep

REPOSITORIES: biostudies-literature