Syntaxin 7 mediates endocytic trafficking to late endosomes.
The lysosome functions are ensured by accurate membrane trafficking in the cell. We found that mouse syntaxin 7 could complement yeast vam3 and pep12 mutants defective in docking/fusion to vacuolar and prevacuolar membranes, respectively. Immunohistochemical studies showed that syntaxin 7 is localized to late endosomes, but not to early endosomes. Induced expression of mutant syntaxin 7 blocked endocytic transport from early to late endosomes but did not block the transport of cathepsin D and lamp-2 from the trans-Golgi network to lysosomes. Thus, syntaxin 7 mediates the endocytic trafficking from early endosomes to late endosomes and lysosomes. These results also suggest that the biosynthetic pathway utilizes a different machinery from that of the endocytic pathway in the docking/fusion to late endosomes.
Nakamura
N
N
Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Japan.
Yamamoto
A
A
Wada
Y
Y
Futai
M
M
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001692:Biological Transport; D002402:Cathepsin D / Q000378:metabolism; D002460:Cell Line; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000235:genetics; D005816:Genetic Complementation Test; D006056:Golgi Apparatus / Q000378:metabolism; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000201:enzymology / Q000378:metabolism; D008561:Membrane Fusion; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D009154:Mutation; D050765:Qa-SNARE Proteins; D051381:Rats; D029701:Saccharomyces cerevisiae Proteins; D014162:Transfection
D015703:Antigens, CD; D005656:Fungal Proteins; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; C107706:VAM3 protein, S cerevisiae; D002402:Cathepsin D