Metabolite of SIR2 reaction modulates TRPM2 ion channel.
The transient receptor potential melastatin-related channel 2 (TRPM2) is a nonselective cation channel, whose prolonged activation by oxidative and nitrative agents leads to cell death. Here, we show that the drug puromycin selectively targets TRPM2-expressing cells, leading to cell death. Our data suggest that the silent information regulator 2 (Sir2 or sirtuin) family of enzymes mediates this susceptibility to cell death. Sirtuins are protein deacetylases that regulate gene expression, apoptosis, metabolism, and aging. These NAD+-dependent enzymes catalyze a reaction in which the acetyl group from substrate is transferred to the ADP-ribose portion of NAD+ to form deacetylated product, nicotinamide, and the metabolite OAADPr, whose functions remain elusive. Using cell-based assays and RNA interference, we show that puromycin-induced cell death is greatly diminished by nicotinamide (a potent sirtuin inhibitor), and by decreased expression of sirtuins SIRT2 and SIRT3. Furthermore, we demonstrate using channel current recordings and binding assays that OAADPr directly binds to the cytoplasmic domain of TRPM2 and activates the TRPM2 channel. ADP-ribose binds TRPM2 with similarly affinity, whereas NAD+ displays almost negligible binding. These studies provide the first evidence for the potential role of sirtuin-generated OAADPr in TRPM2 channel gating.
Grubisha
Olivera
O
Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239, USA.
Rafty
Louise A
LA
Takanishi
Christina L
CL
Xu
Xiaojie
X
Tong
Lei
L
Perraud
Anne-Laure
AL
Scharenberg
Andrew M
AM
Denu
John M
JM
D000246:Adenosine Diphosphate Ribose / Q000737:chemistry; D017209:Apoptosis; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D006801:Humans; D015640:Ion Channel Gating; D009536:Niacinamide / Q000737:chemistry; D011485:Protein Binding; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011691:Puromycin / Q000494:pharmacology; D034622:RNA Interference; D056564:Sirtuin 1; D037761:Sirtuins / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000737:chemistry / Q000378:metabolism*
D003432:Cross-Linking Reagents; D011500:Protein Synthesis Inhibitors; D050053:TRPM Cation Channels; C121934:TRPM2 protein, human; D000246:Adenosine Diphosphate Ribose; D009536:Niacinamide; D011691:Puromycin; D003513:Cycloheximide; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D037761:Sirtuins