Conserved motifs in the complete amino acid sequences of the mammalian IFITM proteins were analyzed by MEME/MAST software (http://meme.sdsc.edu/meme/website/intro.html). The secondary structure of IFITM proteins was predicted using SMART (http://smart.embl-heidelberg.de/smart). The logo pictures were generated by Weblogo (http://weblogo.berkeley.edu).