We have previously described the primary structure of the entire met domain and part of the tpr domain present in the human tpr-met oncogene. The isolation and sequencing of an additional cDNA clone now enables us to present the complete primary sequence of the tpr domain. A computer search has unearthed a remarkable identity between tpr and a rat sequence found at the 5-prime end of the activated raf oncogene. The occurrence of tpr-like sequences in combination with two oncogenes suggests that tpr contributes a domain(s) relevant to the observed activation of met and raf.