Identify HILPS-interacting proteins and HIF1a phosphorylation sites

To dissect the molecular mechanisms of HILPS in promoting cell survival under hypoxia, we conducted RNA pull-down assay in combination with mass spectrometry analysis to identify HILPS-interacting proteins. Pull-down of antisense HILPS was used as a negative control. To identify the potential phosphorylation site(s), we conducted the in vitro kinase assay in combination with mass spectrometry analysis using PLK1-T210D, recombinant GST-HIF1a and cold ATP. A kinase assay using PLK1-K82R was included as a control.