Localization of HC expressed alone, LC expressed alone, and HC and LC expressed together. COS cells were transiently transfected with plasmids encoding HC alone ( A–D ), LC alone ( E and F ) or both HC and LC ( G–J ). The expressed proteins were localized by immunofluorescence microscopy. ( A and B ) HC was detected with an anti–myc monoclonal antibody followed by Rhodamine Red-X–labeled anti–mouse secondary antibody. ( C and D ) Cells were double labeled for HC and MTs. HC was detected with anti–myc polyclonal and Oregon green 488–labeled anti–rabbit antibodies, and tubulin was detected with antitubulin monoclonal and Rhodamine Red-X–labeled anti–mouse secondary antibodies. ( E and F ) LC was detected with anti–HA polyclonal and Oregon green 488–labeled anti–rabbit secondary antibodies. ( G–J ) Cells were double labeled for HC and LC. HC was detected with anti–myc monoclonal and Rhodamine Red-X–labeled anti–mouse antibodies, and LC was detected with anti–HA polyclonal and Oregon green 488– labeled anti–rabbit secondary antibodies. Bar, 10 μm.