PMID: 19666031 , Related PDB id: 2KIV
Authors:
Kurabi A, Brener S, Mobli M, Kwan JJ, Donaldson LW
Title:
A nuclear localization signal at the SAM-SAM domain interface of AIDA-1 suggests a requirement for domain uncoupling prior to nuclear import.
Journal:
J Mol Biol. 2009 Oct 9;392(5):1168-77. 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.