Biochemical and molecular modeling studies of the interaction between human CEP55 and TEX14

To arrest the normal cell abscission in mammalian cells, testis-expressed gene 14 (TEX14) competitively binds to the midbody protein centrosomal protein 55 kDa (CEP55). To gain further insights into the interactions between CEP55 and TEX14 (or ALIX), we performed molecular modeling studies. Molecular dynamics simulation indicated that CEP55-EABR (ESCRT and ALIX-binding region) formed a stable coiled coil in the absence of TEX14 (or ALIX) peptides. We also identified interaction sites between CEP55-EABR and TEX14 (or ALIX) responsible for the stability of the complex by calculating H-bonding and van der Waals interaction maps. Biochemical studies also suggested that CEP55 (residues 230-464) forms an elongated coiled coil. The overall architecture of CEP55 and detailed analyses of the interactions between CEP55-EABR and TEX14 (or ALIX) gives more specific atomistic details about interactions between CEP55 and TEX14 (or ALIX), which is not easy to identify in experiments.