Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Cell Sci. 2011 Jun 15;124(Pt 12):2077-85. doi: 10.1242/jcs.078923. Epub 2011 May 24.

Samp1 is functionally associated with the LINC complex and A-type lamina networks.

Author information

  • 1Department of Neurochemistry, Stockholm University, SE10691 Stockholm, Sweden.

Abstract

The transmembrane inner nuclear membrane (INM) protein Samp1 is required for anchoring centrosomes near the nuclei. Using high-resolution fluorescence microscopy we show that Samp1 is distributed in a distinct and characteristic pattern in the nuclear envelope (NE), where it partially colocalizes with the LINC complex protein Sun1. By studying the localization of Samp1 deletion mutants and fusion proteins, we conclude that the cysteine-rich N-terminal half of Samp1 is nucleoplasmically exposed and is responsible for targeting to the INM. It contains four conserved CxxC motifs with the potential to form zinc fingers. The distribution of cysteine-to-alanine substitution mutants, designed to prevent zinc finger formation, showed that NE localization of Samp1 depends on intact CxxC motifs. Overexpression of Samp1 zinc finger mutants produced an abnormal dominant phenotype characterized by disrupted organization of a selective subset NE proteins, including emerin, Sun1, endogenous Samp1 and, in some cases, lamin A/C, but not lamin B, Sun2 or nucleoporins. Silencing of Samp1 expression showed that emerin depends on Samp1 for its correct localization in the NE. Our results demonstrate that Samp1 is functionally associated with the LINC complex protein Sun1 and proteins of the A-type lamina network.

PMID:
21610090
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire
    Loading ...
    Write to the Help Desk