Reprobing showed that p53 was also recovered by Ub-agarose beads, but only in cells overexpressing ING1b. This suggests the development of Ub-ING1b-p53-complexes, Deforolimus Considering that p53 was not observed in the absence of ING1b-overexpression. Given that the ING2-PHD was needed for activating p53, we subsequent examined if an ING1-carboxyl-terminal deletion stabilized unmodified and/or monoubiquitinated p53. Wt-, but not the deleted form of ING1 stabilized the two endogenous and ectopically expressed p53 to a diploma comparable to the result of the proteasome-inhibitor MG132. Considering that ING1 promoted accumulation of ubiquitinated forms of p53, we examined the ING1 protein sequence for motifs known to be included in Ub-binding. We discovered a UBD adjacent to the ING1 PHD, which was earlier described as a PBR, needed and adequate for the binding of PIs. Nuclear magnetic resonance evaluation has revealed that UBD binding can block accessibility to the K48 residue of Ub, thus blocking polyubiquitination that targets proteins to the proteasome. Provided that numerous proteins Torin 2 distributor affecting proteasomal pathways have UBDs, this proposed a part for ING1 in regulating p53 stability through this pathway.