Figure 3. Model of PARP1 interaction with histone H2Av.
Nucleosome with H2Av works as a high affinity site (red) for PARP1 (blue) binding with specific chromatin domains. While in complex with H2Av-nucleosome, PARP1 is catalytically inactive. Phosphorylation of H2Av disrupts its interaction with PARP1 and stimulates PARP1 activity (poly(ADP-ribosylation)). PARP1 modifies histone H1 (Aubin et al., 1983) and facilitates local chromatin relaxation and remodeling.
