A nuclear localization signal at the SAM-SAM domain interface of AIDA-1 suggests a requirement for domain uncoupling prior to nuclear import

J Mol Biol. 2009 Oct 9;392(5):1168-77. doi: 10.1016/j.jmb.2009.08.004. Epub 2009 Aug 8.

Abstract

The neuronal scaffolding protein AIDA-1 is believed to act as a convener of signals arising at postsynaptic densities. Among the readily identifiable domains in AIDA-1, two closely juxtaposed sterile alpha motif (SAM) domains and a phosphotyrosine binding domain are located within the C-terminus of the longest splice variant and exclusively in four shorter splice variants. As a first step towards understanding the possible emergent properties arising from this assembly of ligand binding domains, we have used NMR methods to solve the first structure of a SAM domain tandem. Separated by a 15-aa linker, the two SAM domains are fused in a head-to-tail orientation that has been observed in other hetero- and homotypic SAM domain structures. The basic nuclear import signal for AIDA-1 is buried at the interface between the two SAM domains. An observed disparity between the thermal stabilities of the two SAM domains suggests a mechanism whereby the second SAM domain decouples from the first SAM domain to facilitate translocation of AIDA-1 to the nucleus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism*
  • Cell Nucleus / metabolism*
  • Intracellular Signaling Peptides and Proteins
  • Models, Molecular
  • Nuclear Localization Signals*
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Structure, Tertiary

Substances

  • ANKS1B protein, human
  • Carrier Proteins
  • Intracellular Signaling Peptides and Proteins
  • Nuclear Localization Signals

Associated data

  • PDB/2KIV