Fig. 6

PARylated HIF-1a triggered its deubiquitylation by USP7 under hypoxic conditions. A Co-immunoprecipitation with anti-HIF-1a, anti-USP7, and anti-IgG were performed to identify the binding between USP7 and HIF-1a under hypoxic conditions. B Lysates from CCA cells treated with MG132 and transfected with HA-Ub and USP7i under hypoxic conditions, and then the level of ubiquitinated HIF-1a was analysed. C Inhibit of USP7 promotes degradation of HIF-1a. HuCCT1-USP7i, QBC939-USP7i and their controls were treated with or without MG132. The expression levels of USP7 and HIF-1a were detected. D Western blotting analysis was used to detect the binding ability between USP7 and HIF-1a in PARP1 knockdown and PARG inhibit CCA cells under hypoxic conditions. E PARylation and ubiquitylation of HIF-1a was detected in four groups under hypoxic conditions, including DMSO, DMSO + USP7i, DMSO + PARGi and DMSO + PARGi + USP7i. F Ubiquitylation of HIF-1a under hypoxic conditions was detected in SKA3 overexpression cells with or without USP7i. G The total protein level of HIF-1a under hypoxic conditions was detected in SKA3 overexpression cells with or without USP7i