Fig. 3

USP21 deubiquitinates and stabilizes BRCA2 via its C-terminus. a IP using anti-HA conjugated beads in HEK293T cells expressing HA-USP21 and the indicated Flag-BRCA2 fragments. A schematic of full-length BRCA2 and BRCA2 C-terminal fragments is shown. b Western blot analysis of the indicated BRCA2 fragments in the presence of empty vector, Myc-USP21 WT (U21 WT), or the Myc-USP21 C221A catalytic mutant (U21 C221A). c Ubiquitination assay in cells expressing HA-Ub and the indicated Flag-BRCA2 fragments in the presence of empty vector (V), U21 WT or U21 C221A. Cells were treated with MG-132 prior to Flag-IP. d BRCA2 western blot analysis in CAPAN-1 cells in the presence or absence of USP21 knockdown. A schematic for the CAPAN-1-specific BRCA2 C-terminal truncation (BRCA2 ΔC) is shown. e BRCA2 western blot analysis of cell expressing the indicated siRNAs in the presence or absence of MG-132 or LMB treatment