Download MendeleyA Conformational Switch in the CRIB-PDZ Module of Par-6.
Whitney, D.S., Peterson, F.C., Volkman, B.F.(2011) Structure 19: 1711-1722
- PubMed: 22078569
- DOI: https://doi.org/10.1016/j.str.2011.07.018
- Primary Citation of Related Structures:
2LC6, 2LC7 - PubMed Abstract:
Here, we report a novel mechanism of PDZ (PSD-95/Dlg/ZO-1) domain regulation that distorts a conserved element of PDZ ligand recognition. The polarity regulator Par-6 assembles a conserved multiprotein complex and is directly modulated by the Rho GTPase Cdc42. Cdc42 binds the adjacent Cdc42/Rac interactive binding (CRIB) and PDZ domains of Par-6, increasing C-terminal ligand binding affinity by 10-fold. By solving structures of the isolated PDZ domain and a disulfide-stabilized CRIB-PDZ, we detected a conformational switch that controls affinity by altering the configuration of the conserved "GLGF" loop. As a result, lysine 165 is displaced from the PDZ core by an adjacent hydrophobic residue, disrupting coordination of the PDZ ligand-binding cleft. Stabilization of the CRIB:PDZ interface restores K165 to its canonical location in the binding pocket. We conclude that a unique "dipeptide switch" in the Par-6 PDZ transmits a signal for allosteric activation to the ligand-binding pocket.
Organizational Affiliation:
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
