Is ATP the Only Nucleoside Triphosphate among ATP, CTP, GTP, and UTP to Have a Role in Kinase Catalysis of Heme-Regulated Inhibitor toward eIF2α during Lung Cancer Development?

The heme-regulated eukaryotic initiation factor 2α (eIF2α) kinase, also known as inhibitor (HRI), detects misfolded proteins and induces cytoprotective response to stress, mainly caused by heme-shortage. nucleoside triphosphate ATP serves the main donor of phosphate for phosphorylation eIF2α HRI in human cells. However, other triphosphates (CTP, GTP, UTP) are present at relatively high concentrations, especially tumor Therefore, this short communication we evaluate role four substrates (namely ATP, CTP, on kinase activity. Additionally, first time, perform a detailed kinetics study G202S mutant, whose presence lung is associated with cancer development. Here, all tested during development discussed from point view results showed that kcat value GTP was lower than but significantly higher those CTP UTP. approximately 20% wild-type, while values UTP were wild-type.