Faculty Collaboration Database

A conformational switch in the CRIB-PDZ module of Par-6. Structure 2011 Nov 09;19(11):1711-22

Date

11/15/2011

Pubmed ID

22078569

Pubmed Central ID

PMC3217198

DOI

10.1016/j.str.2011.07.018

Scopus ID

2-s2.0-80855128793 (requires institutional sign-in at Scopus site)   20 Citations

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.

Author List

Whitney DS, Peterson FC, Volkman BF

Authors

Francis C. Peterson PhD Professor in the Biochemistry department at Medical College of Wisconsin
Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Allosteric Regulation
Amino Acid Motifs
Animals
Binding Sites
Conserved Sequence
Drosophila Proteins
Drosophila melanogaster
Magnetic Resonance Spectroscopy
Models, Molecular
PDZ Domains
Protein Binding
Protein Kinase C