Recently we described the cloning of the yeast tms1 gene by complementation of a lethal growth arrest caused by expression of a tumour mutant cDNA of p53 in fission yeast. The tms1 gene product was found to form stable complexes with p53 in yeast and in vitro using purified recombinant proteins the interaction was mapped to the C-terminal region of p53. Using a combination of a genetic and a synthetic approach we were able to establish the p53 binding site on the tms1 protein to the sequence YMITTED FCT (aa 116-125) in the vicinity of a well conserved cell division motif.