Pérez-Sancho Jessica, Vanneste Steffen, Lee Eunkyoung, McFarlane Heather E, Esteban Del Valle Alicia, Valpuesta Victoriano, Friml Jiří, Botella Miguel A, Rosado Abel
Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, 29071 Malaga, Spain (J.P.-S., A.E.d.V., V.V., M.A.B., A.R.);Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052 Ghent, Belgium (S.V., J.F.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (S.V., J.F.);Department of Botany, Faculty of Sciences, University of British Columbia, Vancouver, Canada V6T 1Z4 (E.L., H.E.M., A.R.); andMax Planck Institute for Molecular Plant Physiology, 14476 Potsdam, Germany (H.E.M.).
Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, 29071 Malaga, Spain (J.P.-S., A.E.d.V., V.V., M.A.B., A.R.);Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052 Ghent, Belgium (S.V., J.F.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (S.V., J.F.);Department of Botany, Faculty of Sciences, University of British Columbia, Vancouver, Canada V6T 1Z4 (E.L., H.E.M., A.R.); andMax Planck Institute for Molecular Plant Physiology, 14476 Potsdam, Germany (H.E.M.)
Plant Physiol. 2015 May;168(1):132-43. doi: 10.1104/pp.15.00260. Epub 2015 Mar 19.
Eukaryotic endoplasmic reticulum (ER)-plasma membrane (PM) contact sites are evolutionarily conserved microdomains that have important roles in specialized metabolic functions such as ER-PM communication, lipid homeostasis, and Ca(2+) influx. Despite recent advances in knowledge about ER-PM contact site components and functions in yeast (Saccharomyces cerevisiae) and mammals, relatively little is known about the functional significance of these structures in plants. In this report, we characterize the Arabidopsis (Arabidopsis thaliana) phospholipid binding Synaptotagmin1 (SYT1) as a plant ortholog of the mammal extended synaptotagmins and yeast tricalbins families of ER-PM anchors. We propose that SYT1 functions at ER-PM contact sites because it displays a dual ER-PM localization, it is enriched in microtubule-depleted regions at the cell cortex, and it colocalizes with Vesicle-Associated Protein27-1, a known ER-PM marker. Furthermore, biochemical and physiological analyses indicate that SYT1 might function as an electrostatic phospholipid anchor conferring mechanical stability in plant cells. Together, the subcellular localization and functional characterization of SYT1 highlights a putative role of plant ER-PM contact site components in the cellular adaptation to environmental stresses.
真核生物内质网（ER）-质膜（PM）接触位点是进化上保守的微结构域，在诸如ER-PM通讯、脂质稳态和Ca(2+)内流等特殊代谢功能中发挥重要作用。尽管最近在酵母（酿酒酵母）和哺乳动物中关于ER-PM接触位点成分和功能的知识有了进展，但对于这些结构在植物中的功能意义却知之甚少。在本报告中，我们将拟南芥的磷脂结合突触结合蛋白1（SYT1）鉴定为哺乳动物延伸突触结合蛋白和酵母三磷酸肌醇结合蛋白家族的ER-PM锚定蛋白在植物中的直系同源物。我们提出SYT1在ER-PM接触位点发挥作用，因为它表现出双重的ER-PM定位，富集在细胞皮层微管缺失区域，并且与已知的ER-PM标记物囊泡相关蛋白27-1共定位。此外，生化和生理分析表明，SYT1可能作为一种静电磷脂锚定蛋白，赋予植物细胞机械稳定性。总之，SYT1的亚细胞定位和功能表征突出了植物ER-PM接触位点成分在细胞适应环境胁迫中的假定作用。
