title: Arabidopsis Synaptotagmin 2 Participates in Pollen Germination and Tube Growth and Is Delivered to Plasma Membrane via Conventional Secretion.
abstract: Arabidopsis synaptotagmin 2 (SYT2) has been reported to participate in an unconventional secretory pathway in somatic cells. Our results showed that SYT2 was expressed mainly in the pollen of Arabidopsis thaliana. The pollen of syt2 T-DNA and RNA interference mutant lines exhibited reduced total germination and impeded pollen tube growth. Analysis of the expression of SYT2-GFP fusion protein in the pollen tube indicates that SYT2 was localized to distinct, patchy compartments but could co-localize with the Golgi markers, BODIPY TR C5 ceramide and GmMan1-mCherry. However, SYT2-DsRed-E5 was localized to the plasma membrane in Arabidopsis suspension cells, in addition to the Golgi apparatus. The localization of SYT2 at the plasma membrane was further supported by immunofluorescence staining in pollen tubes. Moreover, brefeldin A treatment inhibited the transport of SYT2 to the plasma membrane and caused SYT2 to aggregate and form enlarged compartments. Truncation of the SYT2-C2AB domains also resulted in retention of SYT2 in the Golgi apparatus. An in vitro phospholipid-binding assay showed that SYT2-C2AB domains bind to the phospholipid membrane in a calcium-dependent manner. Take together, our results indicated that SYT2 was required for pollen germination and pollen tube growth, and was involved in conventional exocytosis.
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Shengcheng
authors.initials: S
authors.lastname: Han
authors.affiliation: Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
authors.forename: Wei
authors.initials: W
authors.lastname: Siao
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Chunqing
authors.initials: C
authors.lastname: Song
authors.affiliation: School of Life Science, Lanzhou University, Lanzhou 730000, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: School of Life Science, Lanzhou University, Lanzhou 730000, China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wu
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Pengyu
authors.initials: P
authors.lastname: Cheng
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Li
authors.affiliation: Comenius University Science Park, Comenius University, Bratislava, Mlynská dolina, 842 15 Bratislava 4, Slovakia.
authors.forename: Ján
authors.initials: J
authors.lastname: Jásik
authors.affiliation: Department of Botany, Faculty of Natural Sciences, Comenius University, Révová 39, 811 02 Bratislava 1, Slovakia.
authors.forename: Karol
authors.initials: K
authors.lastname: Mičieta
authors.affiliation: Department of Molecular Biology, Comenius University, Faculty of Natural Sciences, Mlynská dolina, pavilion B-2, 842 15 Bratislava 4, Slovakia.
authors.forename: Ján
authors.initials: J
authors.lastname: Turňa
authors.affiliation: Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Voigt
authors.affiliation: Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany; Institute of Botany, Slovak Academy of Sciences, Dubravska cesta 9, SK-84523 Bratislava, Slovak Republic. Electronic address: baluska@uni-bonn.de.
authors.forename: František
authors.initials: F
authors.lastname: Baluška
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Yingdian
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China. Electronic address: hpzhao@bnu.edu.cn.
authors.forename: Heping
authors.initials: H
authors.lastname: Zhao
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018525:Germination; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism; D011058:Pollen / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D053205:Pollen Tube / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D050861:Synaptotagmin II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D050861:Synaptotagmin II
keywords: C2 domains; calcium-dependent phospholipid binding; conventional secretion; pollen germination; synaptotagmins