Fig. 8.

Biosynthetic trafficking of endogenous lysosomal cargo. Pulse-chase analysis of TbCatL (A) and p67 (B) trafficking was performed on control (tet−) and TbRab7 silenced (tet+) BSF cells. (A, top) Radiolabelled TbCatL was specifically immunoprecipitated from cell lysates at the indicated chase times, fractionated by SDS-PAGE (10⁷ cell equivalents/lane), and visualized by phosphorimaging. A representative image is presented with mobilities of immature proprotein (I), uncharacterized precursor form (X), and mature lysosomal form (M) indicated. All lanes are from the same gel/phosphoimage with identical contrasting. Vertical stripe indicates digitally excised irrelevant lanes. (A, bottom) Quantification of TbCatL processing (means ± SEM, n = 3). Precursor (I + X) and mature forms (M) are presented as a percentage of initial species (I + X). (B, top) Representative phosphorimage of immunoprecipitated p67 (10⁷ cell equivalents/lane) from control cells only. Mobilities of initial ER gp100, Golgi-modified gp150, and quasi-stable lysosomal gp75, gp42, and gp32 glycoforms are indicated. (B, bottom) Quantification p67 processing (means ± SEM, n = 3). Data shown are gp100 and gp32 glycoforms presented as a percentage of initial gp100.