Recombinant Human Fructose-2,6-bisphosphatase TIGAR protein (TIGAR)

Function

Fructose-bisphosphatase hydrolyzing fructose-2,6-bisphosphate as well as fructose-1,6-bisphosphate (PubMed:19015259). Acts as a negative regulator of glycolysis by lowering intracellular levels of fructose-2,6-bisphosphate in a p53/TP53-dependent manner, resulting in the pentose phosphate pathway (PPP) activation and NADPH production (PubMed:16839880, PubMed:22887998). Contributes to the generation of reduced glutathione to cause a decrease in intracellular reactive oxygen species (ROS) content, correlating with its ability to protect cells from oxidative or metabolic stress-induced cell death (PubMed:16839880, PubMed:19713938, PubMed:22887998, PubMed:23726973, PubMed:23817040). Plays a role in promoting protection against cell death during hypoxia by decreasing mitochondria ROS levels in a HK2-dependent manner through a mechanism that is independent of its fructose-bisphosphatase activity (PubMed:23185017). In response to cardiac damage stress, mediates p53-induced inhibition of myocyte mitophagy through ROS levels reduction and the subsequent inactivation of BNIP3. Reduced mitophagy results in an enhanced apoptotic myocyte cell death, and exacerbates cardiac damage (By similarity). Plays a role in adult intestinal regeneration; contributes to the growth, proliferation and survival of intestinal crypts following tissue ablation (PubMed:23726973). Plays a neuroprotective role against ischemic brain damage by enhancing PPP flux and preserving mitochondria functions (By similarity). Protects glioma cells from hypoxia- and ROS-induced cell death by inhibiting glycolysis and activating mitochondrial energy metabolism and oxygen consumption in a TKTL1-dependent and p53/TP53-independent manner (PubMed:22887998). Plays a role in cancer cell survival by promoting DNA repair through activating PPP flux in a CDK5-ATM-dependent signaling pathway during hypoxia and/or genome stress-induced DNA damage responses (PubMed:25928429). Involved in intestinal tumor progression (PubMed:23726973)

Subcellular Location

Cytoplasm; Nucleus; Mitochondrion

Tissue Specificity

Expressed in the brain (PubMed:22887998). Expressed in breast tumors (PubMed:21820150). Expressed in glioblastomas (PubMed:22887998)

Subunit

Interacts with HK2; the interaction increases hexokinase HK2 activity in a hypoxia- and HIF1A-dependent manner, resulting in the regulation of mitochondrial membrane potential, thus increasing NADPH production and decreasing intracellular ROS levels (PubMed:23185017)

• White K.E. et al. Autosomal dominant hypophosphataemic rickets is associated with mutations in FGF23. — Nat. Genet. (2000)
• Cheng J. et al. Screening and cloning of the target genes transactivated by human gene 2 transactivated by nonstructural protein 3 of Hepatitis C virus using suppression subtractive hybridization technique. (SEP-)
• Ota T. et al. Complete sequencing and characterization of 21,243 full-length human cDNAs. — Nat. Genet. (2004)
• Mural R.J. et al. PubMed: CI-5GBD0VIIJ7C63 (SEP-)
• The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). — Genome Res. (2004)
• Jen K.Y. et al. Identification of novel p53 target genes in ionizing radiation response. — Cancer Res. (2005)
• Bensaad K. et al. TIGAR, a p53-inducible regulator of glycolysis and apoptosis. — Cell (2006)
• Matsuoka S. et al. ATM and ATR substrate analysis reveals extensive protein networks responsive to DNA damage. — Science (2007)