Both the transcriptional regulator C-terminal binding protein (CtBP) and the mammalian target of rapamycin complex 1 (mTORC1) (54) were discovered to promote glutamine metabolism and tumor proliferation in various cancer contexts by repressing the expression of Sirt4 directly (55) and indirectly (54), respectively (Figure 1E). The gene discussed is SIRT4; the disease is cancer.