Fig. 1.

Dimerization of CeTIR stimulates NAD⁺ loss and neuronal cell death. (A) Scheme for TIR dimerization via fusing Frb and Fkbp moieties to the TIR domain. Rapamycin stimulates TIR dimerization and cell death. (B) Images of embryonic DRGs expressing the indicated Frb/Fkbp TIR constructs after rapamycin addition. Dying cells are labeled with ethidium homodimer and costained with Hoescht to label nuclei. (C) Quantification of cellular death after rapamycin addition. (D) ΔΨ was monitored with tetramethylrhodamine methyl ester in DRG neurons expressing the indicated Frb/Fkbp TIR construct after rapamycin addition. (E and F) NAD⁺ and ATP levels were measured from DRGs expressing the indicated Frb/Fkbp TIR construct after rapamycin addition. (G and H) NAD⁺ and ATP were measured at more extended time points after rapamycin addition to assess metabolite levels after long-term TIR dimerization. Error bars reflect ± SEM (n = 3). (Scale bars, 25 μM.)