Macro domain, BAL_like family. The macro domain is a high-affinity ADP-ribose binding module found in a variety of proteins as a stand-alone domain or in combination with other domains like in histone macroH2A and some PARPs (poly ADP-ribose polymerases). Some macro domains recognize poly ADP-ribose as a ligand. Previously identified as displaying an Appr-1"-p (ADP-ribose-1"-monophosphate) processing activity, the macro domain may play roles in distinct ADP-ribose pathways, such as the ADP-ribosylation of proteins, an important post-translational modification which occurs in DNA repair, transcription, chromatin biology, and long-term memory formation, among other processes. Members of this family show similarity to BAL (B-aggressive lymphoma) proteins, which contain one to three macro domains. Most BAL family macro domains belong to this family except for the most N-terminal domain in multiple-domain containing proteins. Most BAL proteins also contain a C-terminal PARP active site and are also named as PARPs. Human BAL1 (or PARP-9) was originally identified as a risk-related gene in diffuse large B-cell lymphoma that promotes malignant B-cell migration. Some BAL family proteins exhibit PARP activity. Poly (ADP-ribosyl)ation is an immediate DNA-damage-dependent post-translational modification of histones and other nuclear proteins. BAL proteins may also function as transcription repressors.