DNAH8 and cancer: To understand their mechanistic impact, we tested all eleven cancer-associated mutations in all biochemical assays (Figure 4). Remarkably, the seven mutants that map to region 1, including the SuppH mutation that faces the post-HSA domain within region 1 (R685H), all conferred a moderate reduction in ATPase activity, while simultaneously increasing DNA translocation—and thus improve the coupling of ATP hydrolysis to DNA translocation (Figure 4A, and mutants H452Y and R685H in Figure 4B).