title: A Distinct Pathway for Polar Exocytosis in Plant Cell Wall Formation.
abstract: Post-Golgi protein sorting and trafficking to the plasma membrane (PM) is generally believed to occur via the trans-Golgi network (TGN). In this study using Nicotiana tabacum pectin methylesterase (NtPPME1) as a marker, we have identified a TGN-independent polar exocytosis pathway that mediates cell wall formation during cell expansion and cytokinesis. Confocal immunofluorescence and immunogold electron microscopy studies demonstrated that Golgi-derived secretory vesicles (GDSVs) labeled by NtPPME1-GFP are distinct from those organelles belonging to the conventional post-Golgi exocytosis pathway. In addition, pharmaceutical treatments, superresolution imaging, and dynamic studies suggest that NtPPME1 follows a polar exocytic process from Golgi-GDSV-PM/cell plate (CP), which is distinct from the conventional Golgi-TGN-PM/CP secretion pathway. Further studies show that ROP1 regulates this specific polar exocytic pathway. Taken together, we have demonstrated an alternative TGN-independent Golgi-to-PM polar exocytic route, which mediates secretion of NtPPME1 for cell wall formation during cell expansion and cytokinesis and is ROP1-dependent.
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhuang
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Angus Ho Yin
authors.initials: AH
authors.lastname: Law
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Teng
authors.initials: T
authors.lastname: Zhao
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Shengwang
authors.initials: S
authors.lastname: Du
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.).
authors.forename: Michael M T
authors.initials: MM
authors.lastname: Loy
authors.affiliation: School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.) ljiang@cuhk.edu.hk.
authors.forename: Liwen
authors.initials: L
authors.lastname: Jiang
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D002455:Cell Division / Q000235:genetics; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis / Q000235:genetics; D005089:Exocytosis; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000166:cytology / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D055571:Secretory Pathway; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure; D014026:Nicotiana / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D049452:Green Fluorescent Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase