The mr-s protein can self-associate in mammalian cells. (A) Schematic drawing of the constructs used for immunoprecipitation assay. HA-tagged or Flag-tagged full-length (amino acids 1 to 542), ΔSAM (amino acids 1 to 400) and SAM (amino acids 401 to 542) regions were inserted into pcDNA3 vector, respectively. (B) The constructs indicated above were transfected into HEK293T cells. Each lane was co-immunoprecipitated by anti-Flag antibody and detected by anti-HA antibody. Input protein lysates are shown in the lower panels. (C) Flag-tagged two site-directed mr-s mutants, Flag-W404A and Flag-G453A were generated and co-transfected with full-HA. Each lane was co-immunoprecipitated by anti-HA antibody and detected by anti-Flag antibody.