Localization of TGN38 to the trans-Golgi network: involvement of a cytoplasmic tyrosine-containing sequence

The following antibodies were used: 7G7, mouse mAb to human Tac (Rubin et al., 1985a) ; anti-Tac, mouse mAb to human Tac (Uchiyama et al., 1981; provided by T. Waldmann, National Institutes of Health, Bethesda, MD); R3134, rabbit polyclonal antibody to human Tac (Sharon et al., 1986; provided by W. Leonard, National Institutes of Health); anti-mannosidase II, rabbit polyclonal antibody to rat c~-mannosidase II (a gift of K. Moremen, University of Georgia, Athens, GA); and anti-TGN38, rabbit polyclonal antibody raised against a rat TGN38 fusion protein (Luzio et al., 1990; Reaves et al., 1992 ; a gift of G. Banfing, University of Bristol, Bristol, U.K.). The rabbit anti-TGN38 antibody recognizes epitopes of the lumenal domain of TGN38 and does not react with the Tac-TGN38 chimeras or mutants used in our studies (Reaves et al., 1992 ; and data not shown). Fluorescently labeled donkey anti-mouse IgG and donkey anti-rabbit IgG suitable for multiple labeling experiments were purchased from Jackson Im-munoResearch (West Grove, PA).