Developmentally regulated trafficking of the lysosomal membrane protein p67 in Trypanosoma brucei.

摘要: p67 is a lysosomal type I membrane glycoprotein of Trypanosoma brucei. In procyclic stage cells trafficks to the lysosome without modification, but in bloodstream Golgi processing adds poly-N-acetyllactosamine N-glycans. both stages proteolytic fragmentation occurs lysosome, turnover approximately nine times faster cells. Trafficking wildtype and mutants missing cytoplasmic (p67DeltaCD) or cytoplasmic/transmembrane domains (p67DeltaTM) was monitored by pulse-chase, surface biotinylation immunofluorescence. Overexpressed normally procyclics, some leaks cell suggesting that targeting machinery saturable. p67DeltaCD p67DeltaTM are delivered secreted, respectively. The membrane/cytoplasmic function correctly when fused GFP indicating these sufficient for stage-specific targeting. contrast, deletion reporters overwhelmingly targeted degraded These findings suggest either redundant developmentally regulated signals/machinery operative this increased endocytic activity prevents export reporters.