DNA-PKcs, HA95, Hsp72, α-and β-tubulin, and Hsp27 specifically associate with EBNA-LP. The specificity and relative efficiency of coimmunoprecipitation of DNA-PKcs, HA95, Ku70 and 80, HSP72, α-and β-tubulin, Hsp27, or p53 with FLP were evaluated by comparing the abundance of these proteins in M2 immunoprecipitates from FLP-expressing and negative-control cell lysates with the abundance of the proteins in 2% of the cell lysates. The proteins were detected by immunoblotting with specific antibodies.