Figure 1.

Proposed model of XPD-dependent activation of apoptosis in response to triplex-induced DNA damage. The formation of triplex structures can result in DNA double strand breaks. XPD is recruited to the triplex-induced double strand break and co-localizes with γH2AX at the damage site. H2AX tyrosine142 (Y142) phosphorylation is an important post-translational modification that differentiates between activation of apoptosis and initiation of DNA repair. XPD is required for H2AX Y142 phosphorylation and subsequent recruitment of pro-apoptotic factors to γH2AX in response to triplex-induced damage.