1X8S: Structure Of The Par-6 Pdz Domain With A Pals1 Internal Ligand

PDZ protein interaction domains are typically selective for C-terminal ligands, but non-C-terminal, 'internal' ligands have also been identified. The PDZ domain from the cell polarity protein Par-6 binds C-terminal ligands and an internal sequence from the protein Pals1/Stardust. The structure of the Pals1-Par-6 PDZ complex reveals that the PDZ ligand-binding site is deformed to allow for internal binding. Whereas binding of the Rho GTPase Cdc42 to a CRIB domain adjacent to the Par-6 PDZ regulates binding of C-terminal ligands, the conformational change that occurs upon binding of Pals1 renders its binding independent of Cdc42. These results suggest a mechanism by which the requirement for a C terminus can be readily bypassed by PDZ ligands and reveal a complex set of cooperative and competitive interactions in Par-6 that are likely to be important for cell polarity regulation.
PDB ID: 1X8SDownload
MMDB ID: 31073
PDB Deposition Date: 2004/8/18
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.5  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 1X8S: dimeric; determined by author and by software (PISA)
Molecular Components in 1X8S
Label Count Molecule
Proteins (2 molecules)
Cg5884-pa(Gene symbol: par-6)
Molecule annotation
Pals1 Peptide
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB