Portal de Periódicos da CAPES

Plant Cytokinesis Requires De Novo Secretory Trafficking but Not Endocytosis

2007; Elsevier BV; Volume: 17; Issue: 23 Linguagem: Inglês

10.1016/j.cub.2007.10.040

1879-0445

Ilka Reichardt, York‐Dieter Stierhof, Ulríke Mayer, Sandra S. Richter, Heinz Schwarz, Karin Schumacher, Gerd Jürgens,

Photosynthetic Processes and Mechanisms

During plant cytokinesis membrane vesicles are efficiently delivered to the cell-division plane, where they fuse with one another to form a laterally expanding cell plate [1Jürgens G. Plant cytokinesis: Fission by fusion.Trends Cell Biol. 2005; 15: 277-283Abstract Full Text Full Text PDF PubMed Scopus (117) Google Scholar, 2Segui-Simarro J.M. Austin 2nd, J.R. White E.A. Staehelin L.A. Electron tomographic analysis of somatic cell plate formation in meristematic cells of Arabidopsis preserved by high-pressure freezing.Plant Cell. 2004; 16: 836-856Crossref PubMed Scopus (233) Google Scholar]. These membrane vesicles were generally believed to originate from Golgi stacks. Recently, however, it was proposed that endocytosis contributes substantially to cell-plate formation [3Dhonukshe P. Baluska F. Schlicht M. Hlavacka A. Samaj J. Friml J. Gadella Jr., T.W. Endocytosis of cell surface material mediates cell plate formation during plant cytokinesis.Dev. Cell. 2006; 10: 137-150Abstract Full Text Full Text PDF PubMed Scopus (211) Google Scholar]. To determine the relative contributions of secretory and endocytic traffic to cytokinesis, we specifically inhibited either or both trafficking pathways in Arabidopsis. Blocking traffic to the division plane after the two pathways had converged at the trans-Golgi network disrupted cytokinesis and resulted in binucleate cells, whereas impairment of endocytosis alone did not interfere with cytokinesis. By contrast, inhibiting ER-Golgi traffic by eliminating the relevant BFA-resistant ARF-GEF [4Richter S. Geldner N. Schrader J. Wolters H. Stierhof Y.-D. Rios G. Koncz C. Robinson D.G. Jürgens G. Functional diversification of closely related ARF-GEFs in protein secretion and recycling.Nature. 2007; 448: 488-493Crossref PubMed Scopus (183) Google Scholar] caused retention of newly synthesized proteins, such as the cytokinesis-specific syntaxin KNOLLE in the ER [5Lauber M.H. Waizenegger I. Steinmann T. Schwarz H. Mayer U. Hwang I. Lukowitz W. Jürgens G. The Arabidopsis KNOLLE protein is a cytokinesis-specific syntaxin.J. Cell Biol. 1997; 139: 1485-1493Crossref PubMed Scopus (398) Google Scholar], and prevented the formation of the partitioning membrane. Our results suggest that during plant cytokinesis, unlike animal cytokinesis, protein secretion is absolutely essential, whereas endocytosis is not.