1. Academic Validation
  2. NOGO-A/RTN4A and NOGO-B/RTN4B are simultaneously expressed in epithelial, fibroblast and neuronal cells and maintain ER morphology

NOGO-A/RTN4A and NOGO-B/RTN4B are simultaneously expressed in epithelial, fibroblast and neuronal cells and maintain ER morphology

  • Sci Rep. 2016 Oct 27;6:35969. doi: 10.1038/srep35969.
Olli Rämö 1 Darshan Kumar 1 Erika Gucciardo 1 Merja Joensuu 1 Maiju Saarekas 1 Helena Vihinen 1 2 Ilya Belevich 1 2 Olli-Pekka Smolander 3 Kui Qian 3 Petri Auvinen 3 Eija Jokitalo 1 2
Affiliations

Affiliations

  • 1 Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
  • 2 Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
  • 3 DNA Sequencing and Genomics Laboratory, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
Abstract

Reticulons (RTNs) are a large family of membrane associated proteins with various functions. NOGO-A/RTN4A has a well-known function in limiting neurite outgrowth and restricting the plasticity of the mammalian central nervous system. On the Other hand, Reticulon 4 proteins were shown to be involved in forming and maintaining endoplasmic reticulum (ER) tubules. Using comparative transcriptome analysis and qPCR, we show here that NOGO-B/RTN4B and NOGO-A/RTN4A are simultaneously expressed in cultured epithelial, fibroblast and neuronal cells. Electron tomography combined with immunolabelling reveal that both isoforms localize preferably to curved membranes on ER tubules and sheet edges. Morphological analysis of cells with manipulated levels of NOGO-B/RTN4B revealed that it is required for maintenance of normal ER shape; over-expression changes the sheet/tubule balance strongly towards tubules and causes the deformation of the cell shape while depletion of the protein induces formation of large peripheral ER sheets.

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