Fig. 5: CCNB1 transfers copper from ATOX1 to CDK1, thereby activating its kinase activity and promoting G2/M transition.
From: Copper is essential for cyclin B1-mediated CDK1 activation
a IP analysis examining interactions of HA-tagged copper chaperone proteins with Flag-CCNB1 in HepG2 cells. In vitro pulldown assay using Ni agarose (b) and co-IP analysis (c) to evaluate CCNB1 and ATOX1 interaction. d BiFC analysis of CCNB1 and ATOX1 interaction. Scale bars represent 100 μm. e ICP-OES-quantified copper contents of purified proteins alone or after their incubations to assess the copper transfer. f Analysis of p53 phosphorylation after incubation with apo- or Cu-states of ATOX1, CCNB1, CDK1, or their different combinations as indicated. g, h Analysis of H1.4 and p53 phosphorylation in cells expressing shATOX1 (g) or expressing both shATOX1 and HA-ATOX1 WT or CBM (h), synchronized to the S phase and treated with copper. i, j Flow cytometry (i) and FUCCI (j) assay to assess the cell cycle progression of HepG2 cells with ATOX1 knockdown. k Mechanistic model of copper-promoting cell cycle progression by activating CDK1. In (i), data are representative of three biologically independent experiments. Source data are provided as a Source Data file.
