Abstract
The subcellular localization of the sorting nexins (SNXs) in higher plants is a matter of controversy. Previous confocal laser scanning microscopy (CLSM studies on root cells from a transgenic Arabidopsis line expressing SNX1-GFP have suggested that this SNX is present on an endosome having characteristics of both the trans-Golgi network (TGN) and the multivesicular body (MVB). In contrast, SNX2a locates exclusively to the TGN when transiently expressed in tobacco mesophyll protoplasts. By performing immunogold electron microscopy on cryofixed Arabidopsis roots, we have tried to clarify the situation. Both SNX1-GFP and endogenous SNX2a locate principally to the TGN. Labeling of MVBs could not be confirmed with any certainty.



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Acknowledgments
The authors would like to thank the German Research Council (DFG) for generous financial support, and Jürgen Kleine-Vehn for providing the SNX1-GFP line.
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Handling Editor: Peter Nick
York-Dieter Stierhof and Corrado Viotti contributed equally to this investigation.
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Stierhof, YD., Viotti, C., Scheuring, D. et al. Sorting nexins 1 and 2a locate mainly to the TGN. Protoplasma 250, 235–240 (2013). https://doi.org/10.1007/s00709-012-0399-1
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DOI: https://doi.org/10.1007/s00709-012-0399-1