Fig. 1

Parkin interacts with HIF-1α. a Parkin protein expression was significantly decreased in breast cancer specimens compared with non-tumor breast tissues as analyzed by IHC. Left panel: representative IHC staining images of Parkin in a human breast TMA. Scale bar: 20 μm. Right panel: summary of IHC staining of Parkin in breast cancer specimens (n = 120) and non-tumor breast tissues (n = 48) in a human breast TMA (TMA-BR2082a; US Biomax). b Parkin mRNA levels were significantly decreased in human breast cancers compared with matched adjacent non-tumor breast tissues (n = 113). The data were obtained from TCGA. In a, b, P < 0.001; two-tailed Student’s t test. c Low Parkin expression was associated with poor relapse-free survival in breast cancer patients. The data were obtained from Kaplan–Meier plotter. Differences between two survival curves were analyzed using the log-rank (Mantel–Cox) test. d Myc-Parkin interacted with HA-HIF-1α in MCF7 cells. Cells were co-transduced with HA-HIF-1α and Myc-Parkin expression vectors for co-IP assays using the anti-Myc (left panels) and anti-HA antibodies (right panels), respectively. e Endogenous Parkin interacted with endogenous HIF-1α in MCF7 cells detected by co-IP assays. Endogenous Parkin was knocked down by shRNA in MCF7 cells as a negative control. f The IBR domain of Parkin is required for Parkin to interact with HIF-1α. MCF7 cells were transduced with vectors expressing WT or different deletion mutants of Myc-Parkin together with the HA-HIF-1α vector for co-IP assays. g The ID domain of HIF-1α is required for HIF-1α to interact with Parkin. MCF7 cells were transduced with vectors expressing WT or different deletion mutants of HA-HIF-1α vectors together with the Myc-Parkin vector for co-IP assays. h The interaction between Parkin and HIF-1α analyzed by in vitro GST (left) and His (right) pull-down assays, respectively, using purified GST-Parkin and His-Trx-HIF-1α proteins