All the references have been added and we now include this aspect of the IFITM3 mechanism in the discussion of the paper. We thank the reviewer for the comment.
Since this paper is primarily studying IFITM localization and clustering at endosomes/lysosomes it should reference studies in which endocytic localization motifs of the IFITMs were identified and characterized (Jia, Cell Microbiol, 2014; Chesarino, JBC, 2014; Li, JBC, 2015) Line 65 states that subsequent studies have failed to confirm an association between SNP rs12252 and severe influenza.