Fig. 3: CHK2 phosphorylates HIF-1α at Thr645 under hypoxic microenvironment.
From: ROS-ATM-CHK2 axis stabilizes HIF-1α and promotes tumor angiogenesis in hypoxic microenvironment
A Colocalization of CHK2 and HIF-1α shown by representative confocal microscopic images of NSCLC tissues and H1299 cells. For H1299 cells, experiments were conducted under normoxia (21% O2) and hypoxia (1% O2), respectively. B, C. Co-IP of endogenous CHK2 with HIF-1α in H1299 cells under normoxia (21% O2) and hypoxia (1% O2). IgG, immunoglobulin G. D Co-IP of endogenous CHK2 with HIF-1α in H1299 cells pretreated with NAC for 4 h and then cultured in 1% O2 for 6 h. E GST-pull-down assay of His-HIF-1α fusion proteins with bacterially expressed GST-CHK2 fragments. Coomassie Brilliant Blue (CBB) staining shows expression of GST and GST-CHK2 fragments. F GST-pull-down assay of His-CHK2 fusion proteins with bacterially expressed GST-HIF-1α fragments. CBB staining shows expression of GST and GST-HIF-1α fragments. G, H Co-IP of exogenous HA-HIF-1α with Flag-CHK2 under normoxia (21% O2) and hypoxia (1% O2) in HEK293-CHK2-KO cells transiently transfected with indicated plasmids.
