CBP80/CBP20 Dependent Translation Initiation Factor (CTIF)

CTIF is a component of the CBP80 (NCBP1)/CBP20 (NCBP2) translation initiation complex that binds cotranscriptionally to the cap end of nascent mRNA. The CBP80/CBP20 complex is involved in a simultaneous editing and translation step that recognizes premature termination codons (PTCs) in mRNAs and directs PTC-containing mRNAs toward nonsense-mediated decay (NMD). On mRNAs without PTCs, the CBP80/CBP20 complex is replaced with cytoplasmic mRNA cap-binding proteins, including EIF4G), and steady-state translation of the mRNAs resumes in the cytoplasm. The deduced 598-amino acid protein had an apparent molecular mass of 78 kD by SDS-PAGE. RT-PCR detected KIAA0427 expression in all adult human tissues examined, with highest expression in brain, followed by lung, kidney, prostate, testis, and ovary.