Rabbit Anti-Securin monoclonal antibody for ICC, IF, WB. Pituitary tumor-transforming gene 1 (PTTG-1) is an oncogene expressed in normal tissues containing proliferating cells and in tumors. PTTG is downstream of the MAP kinase signaling cascade and is phosphorylated at Ser162 by MAPK in vitro. Phosphorylation plays an essential role in PTTG's transactivation function. The PTTG protein contains a DNA-binding domain, and it activates transcription of the c-Myc oncogene by binding to the promoter to form a complex. Studies have demonstrated that expression of human PTTG correlates with cell proliferation in a cell cycledependent manner, and the association of human PTTG with Ku, the regulatory subunit of DNA-dependent protein kinase, is disrupted when a DNA double-strand breaks occurs.