Lamin A/C-dependent localization of Nesprin-2, a giant scaffolder at the nuclear envelope

Mol Biol Cell. 2005 Jul;16(7):3411-24. doi: 10.1091/mbc.e04-11-1009. Epub 2005 Apr 20.

Abstract

The vertebrate proteins Nesprin-1 and Nesprin-2 (also referred to as Enaptin and NUANCE) together with ANC-1 of Caenorhabditis elegans and MSP-300 of Drosophila melanogaster belong to a novel family of alpha-actinin type actin-binding proteins residing at the nuclear membrane. Using biochemical techniques, we demonstrate that Nesprin-2 binds directly to emerin and the C-terminal common region of lamin A/C. Selective disruption of the lamin A/C network in COS7 cells, using a dominant negative lamin B mutant, resulted in the redistribution of Nesprin-2. Furthermore, using lamin A/C knockout fibroblasts we show that lamin A/C is necessary for the nuclear envelope localization of Nesprin-2. In normal skin where lamin A/C is differentially expressed, strong Nesprin-2 expression was found in all epidermal layers, including the basal layer where only lamin C is present. This indicates that lamin C is sufficient for proper Nesprin-2 localization at the nuclear envelope. Expression of dominant negative Nesprin-2 constructs and knockdown studies in COS7 cells revealed that the presence of Nesprin-2 at the nuclear envelope is necessary for the proper localization of emerin. Our data imply a scaffolding function of Nesprin-2 at the nuclear membrane and suggest a potential involvement of this multi-isomeric protein in human disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • COS Cells
  • Caenorhabditis elegans
  • Cell Line, Tumor
  • Cell Nucleus / metabolism
  • Cytoplasm / metabolism
  • Drosophila melanogaster
  • Genes, Dominant
  • Glutathione Transferase / metabolism
  • Humans
  • Immunoblotting
  • Immunohistochemistry
  • Immunoprecipitation
  • In Vitro Techniques
  • Lamin Type A / biosynthesis*
  • Membrane Proteins / metabolism
  • Microfilament Proteins / biosynthesis*
  • Microscopy, Fluorescence
  • Models, Biological
  • Models, Genetic
  • Mutation
  • Nerve Tissue Proteins / biosynthesis*
  • Nuclear Envelope / metabolism*
  • Nuclear Proteins / biosynthesis*
  • Plasmids / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • RNA, Small Interfering / metabolism
  • Thymopoietins / metabolism
  • Transfection
  • Two-Hybrid System Techniques

Substances

  • Lamin Type A
  • Membrane Proteins
  • Microfilament Proteins
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • RNA, Small Interfering
  • SYNE2 protein, human
  • Thymopoietins
  • emerin
  • lamin C
  • Glutathione Transferase