The BiFC plasmids (pBiFC-VN1-173, pBiFC-VC155-238) were the gift of Prof. Péter Várnai (Semmelweis University, Budapest). To insert the FL TPPP/p25 cDNA in either the pBiFC-VN1-173 or pBiFC-VC155-238 the following primers for polymerase chain reaction (PCR) amplification were used: forward 5-GAAGGAGCTCGAGATATGGCTGACAAGGCTAAGC-3 and reverse 5-CCGTGGATCCCTACTTGCCCCCTTGCACCTTCTGGTCGTAGG-3 and pET21c-TPPP/p25 as a template. The PCR product, following purification and after digestion with XhoI-BamHI restriction enzymes, was inserted to XhoI and BamHI sites in the BiFC vectors. To insert the CORE segment of TPPP/p25 (TPPP/p25 delta 3–43/delta 175–219) cDNA in either the pBiFC-VN1-173 or pBiFC-VC155-238, the following primers for PCR amplification were used: forward 5- GGAATTC TATGGCTGCATCCCCTGAG-3 and reverse 5- ATGGATCCCTAGCCCGTGAACTTGGT-3′ and pET21c-TPPP/p25 as a template. The PCR product, following purification and after digestion with EcoRI-BamHI restriction enzymes, was inserted to EcoRI and BamHI sites in the BiFC vectors. The sequences of all construct were verified by restriction mapping and sequencing.