Rice SCAMP1 defines clathrin-coated, trans-Golgi-located tubular-vesicular structures as an early endosome in tobacco BY-2 cells

• Verfasst von: Lam, Sheung Kwan [VerfasserIn]
• Verfasst von: Hillmer, Stefan [VerfasserIn]
• Verfasst von: Robinson, David G. [VerfasserIn]
• Titel: Rice SCAMP1 defines clathrin-coated, trans-Golgi-located tubular-vesicular structures as an early endosome in tobacco BY-2 cells
• Verf.angabe: Sheung Kwan Lam, Ching Lung Siu, Stefan Hillmer, Seonghoe Jang, Gynheung An, David G. Robinson and Liwen Jiang
• Umfang: 24 S.
• Fussnoten: Gesehen am 17.05.2017
• Titel Quelle: Enthalten in: The plant cell
• Jahr Quelle: 2007
• Band/Heft Quelle: 19(2007), 1, S. 296-319
• ISSN Quelle: 1532-298X
• DOI: doi:10.1105/tpc.106.045708
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1558699848

Abstract

We recently identified multivesicular bodies (MVBs) as prevacuolar compartments (PVCs) in the secretory and endocytic pathways to the lytic vacuole in tobacco (Nicotiana tabacum) BY-2 cells. Secretory carrier membrane proteins (SCAMPs) are post-Golgi, integral membrane proteins mediating endocytosis in animal cells. To define the endocytic pathway in plants, we cloned the rice (Oryza sativa) homolog of animal SCAMP1 and generated transgenic tobacco BY-2 cells expressing yellow fluorescent protein (YFP)-SCAMP1 or SCAMP1-YFP fusions. Confocal immunofluorescence and immunogold electron microscopy studies demonstrated that YFP-SCAMP1 fusions and native SCAMP1 localize to the plasma membrane and mobile structures in the cytoplasm of transgenic BY-2 cells. Drug treatments and confocal immunofluorescence studies demonstrated that the punctate cytosolic organelles labeled by YFP-SCAMP1 or SCAMP1 were distinct from the Golgi apparatus and PVCs. SCAMP1-labeled organelles may represent an early endosome because the internalized endocytic markers FM4-64 and AM4-64 reached these organelles before PVCs. In addition, wortmannin caused the redistribution of SCAMP1 from the early endosomes to PVCs, probably as a result of fusions between the two compartments. Immunogold electron microscopy with high-pressure frozen/freeze-substituted samples identified the SCAMP1-positive organelles as tubular-vesicular structures at the trans-Golgi with clathrin coats. These early endosomal compartments resemble the previously described partially coated reticulum and trans-Golgi network in plant cells.