An engineered four-stranded coiled coil substitutes for the tetramerization domain of wild-type p53 and alleviates transdominant inhibition by tumor-derived p53 mutants.

The tetramerization domain of p53 is required for efficient tumor suppressor activity. This domain, however, also allows wild-type p53 to heterooligomerize with dominant negative tumor-derived p53 mutants. We explored the feasibility of substituting the native tetramerization domain of wild-type p53 with an engineered leucine zipper that assembles as a four-stranded coiled coil. The engineered zipper drove p53 tetramerization in vitro and p53 function in vivo. Furthermore, it alleviated transdominant inhibition by tumor-derived p53 mutants, implying that dominant negative mutants act by hetero-oligomerizing with wild-type p53. The ability of the engineered zipper to drive tetramerization was critical for p53 function, since p53 dimers, formed by substituting the p53 tetramerization domain with a native leucine zipper, were weak tumor suppressors.