1. PALB2 is recruited by a pathway that mediates and recognizes protein ubiquitination at sites of DNA damage.
PALB2 is recruited by a pathway that mediates and recognizes protein ubiquitination at sites of DNA damage. (A) Images demonstrating suppression of endogenous PALB2 foci in U2OS cells depleted of RAP80, RNF8 or MDC1, but not NBS1, upon exposure to IR. PALB2 foci are shown in red and γ-H2AX foci are green. Colocalization is seen as yellow signal in cells transfected with siLacZ (control) or siNBS1. (B) Quantification of the assembly of endogenous PALB2 foci in U2OS cells depleted of NBS1, RAP80, RNF8 or MDC1. The percentage of cells depleted of RAP80, RNF8 or MDC1 that contained PALB2 foci was statistically different from cells treated with a control siRNA directed against LacZ or depleted of NBS1 (P<0.0001). Each value represents the mean ± SD of three counts of 150 or more cells from the same coverslip. (C) Immunoblots demonstrating depletion of endogenous RAP80 and reconstitution with a N-terminally tagged (Flag-HA) RAP80 cDNA that was resistant to the siRNA. (D) Quantification of endogenous PALB2 foci in U2OS cells depleted of RAP80 and reconstituted with a siRNA-resistant RAP80 cDNA or with vector alone. Each value represents the mean ± SD of three counts of 150 or more cells from the same coverslip. (E) Images demonstrating colocalization of PALB2 with ubiquitin, as detected by the FK2 antibody, in U2OS cells at 16 h after 10 Gy IR. Colocalization is evident in the merged image as yellow foci.
Fan Zhang et al. J Cell Sci 2012;125:
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