CTIF is a component of the CBP80 (NCBP1; MIM 600469)/CBP20 (NCBP2; MIM 605133) 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 (MIM 600495), and steady-state translation of the mRNAs resumes in the cytoplasm (Kim et al., 2009 [PubMed 19648179]).[supplied by OMIM, Dec 2009].