Endolysosomal proteins are exported from the Golgi complex in two distinct populations of transport carriers. (a–c) HeLa cells coexpressing streptavidin–KDEL with each of the indicated reporter proteins were treated with biotin and imaged live by spinning-disk confocal microscopy. The left panel shows single frames captured at the indicated times after addition of biotin. The right panel shows magnified images of the boxed areas. (d–f) HeLa cells coexpressing streptavidin–KDEL with combinations of the indicated reporter constructs were analyzed as in a–c. The left columns show single frames captured at the indicated times after addition of biotin (from Video 2 in d and Video 3 in e). The right columns show magnified images of the boxed areas. Bars: (low magnification) 5 µm; (high magnification) 1 µm.