The tetratricopeptide repeat (TPR) motif is a degenerate, 34 amino acid sequence found in many proteins and acts to mediate protein-protein interactions in various pathways. At the sequence level, there can be up to 16 tandem TPR repeats, each of which has a helix-turn-helix shape that stacks on other TPR repeats to achieve ligand binding specificity. TTC30A (tetratricopeptide repeat domain 30A) and TTC30B (tetratricopeptide repeat domain 30B) are cell projection proteins that belong to the TTC30/dfy-1/fleer family. TTC30A and TTC30B contain eight TPR repeats and may be required for polyglutamylation of axonemal tubulin. Both TTC30A and TTC30B may be involved in anterograde intraflagellar transport (IFT), which is a process where cilia precursors are transported from the base of the cilium to the site of incorporation at the tip. TTC30A and TTC30B consists of 665 amino acids and are encoded by a gene located on human chromosome 2q31.2.