I-kappa-B- (IkB)-like protein that inhibits the binding of NF-kappa-B to DNA, thereby down-regulating pro-inflammatory cytokine production (By similarity). Forms a heterodimer with the NF-kappa-B subunit RELA/p65 and prevents the activation of the NF-kappa-B transcription factor (PubMed:10934190). Also inhibits the host calcineurin phosphatase activity, which is required for the induction of nuclear factor of activated T cells(NFAT)-dependent immune response genes (By similarity). Inhibits calcineurin function, which is required for the induction of nuclear factor of activated T cells (NFAT)-dependent immune response genes (By similarity). Prevents the binding of substrates to calcineurin without affecting the phosphatase activity (By similarity). Does not contain the serine residues that are phosphorylated by host IkB kinase and thus is not degraded following stimulation of the NFkB pathway (PubMed:10934190). Interacts with host PPIA (By similarity). Interacts with host PPP3CA/Calcineurin (PubMed:18261759). Interacts with host RELA/p65; interaction of the 32 kDa form with host RELA results in the formation of a stable complex with NF-kappa-B (PubMed:10934190). Interacts with host PPP3R1 (By similarity). Interacts with host EP300; this interaction inhibits the association of host EP300 with host RELA, JUN and NFATC2 (PubMed:16365438). Binding to host PPP3CA/Calcineurin may mask the second nuclear localization signal thereby contributing to the cytoplasmic retention of A238L. Expressed in the early phase of the viral replicative cycle. The C-terminal region contains the docking motifs PxIxITxC and FLCV, which are required and sufficient for binding to host calcineurin. The protein exists in a 28 kDa and a 32 kDa form, probably due to post-translational modifications which are neither phosphorylation, nor sumoylation. Belongs to the asfivirus A238L family.