The inner nuclear membrane protein Sun1 mediates the anchorage of Nesprin-2 to the nuclear envelope

Research output: Contribution to journalArticle

  • External authors:
  • V. C. Padmakumar
  • Thorsten Libotte
  • Wenshu Lu
  • Hafida Zaim
  • Angelika A. Noegel
  • Josef Gotzmann
  • Roland Foisner
  • Iakowos Karakesisoglou


Nesprins form a novel class of nuclear envelope-anchored spectrin-repeat proteins. We show that a direct association of their highly conserved C-terminal luminal domain with the inner nuclear membrane protein Sun1 mediates their nuclear envelope localisation. In Nesprin-1 and Nesprin-2 the conserved C-terminal amino acids PPPX are essential for the interaction with a C-terminal region in Sun1. In fact, Sun1 is required for the proper nuclear envelope localisation of Nesprin-2 as shown using dominant-negative mutants and by knockdown of Sun1 expression. Sun1 itself does not require functional A-type lamins for its localisation at the inner nuclear membrane in mammalian cells. Our findings propose a conserved nuclear anchorage mechanism between Caenorhabditis elegans and mammals and suggest a model in which Sun1 serves as a 'structural bridge' connecting the nuclear interior with the actin cytoskeleton.

Bibliographical metadata

Original languageEnglish
Pages (from-to)3419-3430
Number of pages11
JournalJournal of Cell Science
Issue number15
Publication statusPublished - 1 Aug 2005