5umz

From Proteopedia

Structure of TNRC6A NLS in complex with importin-alpha

PDB ID 5umz

Drag the structure with the mouse to rotate

Structural highlights

5umz is a 3 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.9Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

IMA1_MOUSE Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus.

Publication Abstract from PubMed

The GW182/TNRC6 family of proteins are central scaffolds that link microRNA-associated Argonaute proteins to the cytoplasmic decay machinery for targeted mRNA degradation processes. Although nuclear roles for the GW182/TNRC6 proteins are unknown, recent reports have demonstrated nucleocytoplasmic shuttling activity that utilises the importin-alpha and importin-beta transport receptors for nuclear translocation. Here we describe the structure of mouse importin-alpha in complex with the TNRC6A nuclear localisation signal peptide. We further show that the interactions observed between TNRC6A and importin-alpha are conserved between mouse and human complexes. Our results highlight the ability of monopartite cNLS sequences to maximise contacts at the importin-alpha major binding site, as well as regions outside the main binding cavities.

Structural characterisation of TNRC6A nuclear localisation signal in complex with importin-alpha.,Chaston JJ, Stewart AG, Christie M PLoS One. 2017 Aug 24;12(8):e0183587. doi: 10.1371/journal.pone.0183587., eCollection 2017. PMID:28837617^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Chaston JJ, Stewart AG, Christie M. Structural characterisation of TNRC6A nuclear localisation signal in complex with importin-alpha. PLoS One. 2017 Aug 24;12(8):e0183587. doi: 10.1371/journal.pone.0183587., eCollection 2017. PMID:28837617 doi:http://dx.doi.org/10.1371/journal.pone.0183587