Younès Bouzidi, Michaël Bosco, Haifei Gao, Stéphanie Pradeau, Lucrèce Matheron, Isabelle Chantret, Patricia Busca, Sébastien Fort, Christine Gravier-Pelletier, Stuart E H Moore
Free polymannose-type oligosaccharides (fOS) are processed by cytosolic enzymes to generate Man 5GlcNAc which is transferred to lysosomes and degraded. Lysosomal fOS import was demonstrated in vitro but is poorly characterized in part due to lack of convenient substrates. As chitooligosaccharides (COS, oligomers β1,4-linked GlcNAc) block [ 3H]Man5GlcNAc transport into lysosomes, we asked if COS are themselves transported and if so, can they be chemically modified to generate fluorescent substrates. We show that COS are degraded by lysosomal hydrolases to generate GlcNAc, and robust ATP-dependent transport of [ 3H]COS2/4 di and tetrasaccharides into intact rat liver lysosomes was observed only after blocking lysosomal [ 3H]GlcNAc efflux with cytochalasin B...
December 9, 2023: Glycobiology