Processes involving DNA transcription, replication and repair are necessary in maintaining normal cell function. For each of these processes, the double stranded NA must first be unwound. This is achieved in an ATP-dependent manner by enzymes termed DNA helicases. Reptin52/TIP49b is a DNA helicase that directly interacts with Pontin52/TIP49a. Reptin52/TIP49b and Pontin52/TIP49a belong to a family of highly conserved proteins that share homology with the bacterial protein RuvB, a helicase involved in double-strand break repair and homologous recombination. Both are TATA binding protein (TBP) interacting proteins that bind to β-Catenin and are among the 12 polypeptides that comprise the INO80 chromatin-remodeling complex. It has also been demonstrated that Reptin52/TIP49b and Pontin52/TIP49a can be found in a complex with the proto- ncogene c-myc. Reptin52/TIP49b and Pontin52/TIP49a have antagonistic roles as Reptin/TIP49b represses gene activation mediated by β-Catenin and c-myc, whereas Pontin52/TIP49a stimulates gene activation. Thus, Reptin52/TIP49b and Pontin52/TIP49a are transcriptional co-factors that work together to help control multiple pathways.