RESUMO
PP2A is composed of a scaffolding subunit (A), a catalytic subunit (C) and a regulatory subunit (B) that is classified into four families including B, B', B'' and B'''/striatin. Here, we found that a distinct PP2A complex regulates NF-κB signalling by dephosphorylation of IKKß, IκBα and RelA/p65. The PP2A core enzyme AC dimer and the holoenzyme AB'''C trimer dephosphorylate IKKß, IκBα and RelA, whereas the ABC trimer dephosphorylates IκBα but not IKKß and RelA in cells. In contrast, AB'C and AB''C trimers have little effect on dephosphorylation of these signalling proteins. These results suggest that different forms of PP2A regulate NF-κB pathway signalling through multiple steps each in a different manner, thereby finely tuning NF-κB- and IKKß-mediated cellular responses.