TTI1 (TELO2 interacting protein 1) is a critical component of the conserved Triple T (TTT) complex, which consists of TELO2, TTI1, and TTI2 1. This complex serves as an essential co-chaperone for phosphatidylinositol 3-kinase-related protein kinases (PIKKs), including mTOR, ATM, ATR, DNA-PKcs, SMG-1, and TRRAP 2. TTI1 provides a structural platform where TELO2 binds to its central region and TTI2 to its C-terminal end, forming an elongated helical repeat structure 3. The TTT complex is crucial for PIKK stability, proper folding, and assembly of mTORC1 and mTORC2 complexes 2. It collaborates with the R2TP chaperone complex and HSP90 to facilitate co-translational maturation of PIKKs 4. TTI1 plays vital roles in DNA damage response, with its N- and C-terminal segments recognizing specific domains of ATM 3. Loss of TTI1 function leads to impaired mTOR pathway activity and causes autosomal-recessive neurodevelopmental disorders characterized by intellectual disability, microcephaly, short stature, and movement disorders 1. Additionally, TTI1 contributes to radioresistance in cancer by activating the ATM pathway 5.