NAD⁺-Consuming Enzymes in Stem Cell Homeostasis

Figure 1

Locations of NAD⁺-consuming enzymes. SIRT1 is reported to locate in both in nucleus and cytosol. SIRT2, predominantly resided in cytosol, may also exist in mitochondria and nucleus. SIRT3 is a major mitochondrial deacetylase and also plays a role in nucleus. SIRT4 is only found in mitochondria. SIRT5 locates in mitochondrial matrix and intermembrane space, cytosol, peroxisome, and nucleus. SIRT6 is only found in nucleus. SIRT7 is the only sirtuin protein that mainly locates in nucleolus. PARPs reside in cytosol, mitochondria, and nucleus. CD38 is observed both in plasma membrane (catalytic domain facing outside or inside) and intracellular membranes (including endoplasmic reticulum, nucleus, mitochondria, and endolysosome). CD157 is a glycophosphatidylinositol-anchored protein with the catalytic domain facing outside. Sterile alpha and Toll/interleukin receptor (TIR) motif-containing 1 (SARM1) locates in cytosol, mitochondria, and nucleus. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is found in mitochondria and nucleus. NAD⁺ kinase (NADK) only resides in cytosol.