This is the C-terminal domain of coiled-coil domain-containing protein 138 (CCDC138), which adopts an alpha-solenoid structure. CCDC138 function is not yet clear. However, it has been localised to basal bodies, suggesting to play a role in centrosomal and ciliary biology [1].

1: Integration of over 9,000 mass spectrometry experiments builds a global map of human protein complexes. Drew K, Lee C, Huizar RL, Tu F, Borgeson B, McWhite CD, Ma Y, Wallingford JB, Marcotte EM; Mol Syst Biol. 2017;13:932. PMID:28596423