title: A conformational switch in the CRIB-PDZ module of Par-6.
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.
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
authors.forename: Dustin S
authors.initials: DS
authors.lastname: Whitney
authors.forename: Francis C
authors.initials: FC
authors.lastname: Peterson
authors.forename: Brian F
authors.initials: BF
authors.lastname: Volkman
mesh_terms: D000494:Allosteric Regulation; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D029721:Drosophila Proteins / Q000737:chemistry*; D004331:Drosophila melanogaster; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D054731:PDZ Domains; D011485:Protein Binding; D011493:Protein Kinase C / Q000737:chemistry*
chemical_list: D029721:Drosophila Proteins; C532584:Par-6 protein, Drosophila; D011493:Protein Kinase C
references.citation: Curr Opin Cell Biol. 2006 Apr;18(2):206-12
references.pmid: 16490351
references.citation: Biochemistry. 2003 Mar 18;42(10):2797-805
references.pmid: 12627945
references.citation: Proteins. 2003 Feb 15;50(3):496-506
references.pmid: 12557191
references.citation: Protein Sci. 2006 Sep;15(9):2149-58
references.pmid: 16882988
references.citation: J Mol Biol. 2002 Mar 8;316(5):1101-10
references.pmid: 11884147
references.citation: J Magn Reson. 2003 Jan;160(1):65-73
references.pmid: 12565051
references.citation: Mol Cell. 2004 Mar 12;13(5):665-76
references.pmid: 15023337
references.citation: Nat Cell Biol. 2003 Feb;5(2):137-42
references.pmid: 12545177
references.citation: Nat Struct Mol Biol. 2004 Nov;11(11):1122-7
references.pmid: 15475968
references.citation: J Biomol NMR. 1999 Mar;13(3):289-302
references.pmid: 10212987
references.citation: Science. 2001 Mar 23;291(5512):2429-33
references.pmid: 11264542
references.citation: Acc Chem Res. 2003 Jul;36(7):530-8
references.pmid: 12859214
references.citation: Nat Cell Biol. 2000 Aug;2(8):531-9
references.pmid: 10934474
references.citation: Proc Natl Acad Sci U S A. 2009 Oct 27;106(43):18249-54
references.pmid: 19828436
references.citation: Nature. 1999 May 27;399(6734):379-83
references.pmid: 10360578
references.citation: Nat Struct Biol. 2000 May;7(5):384-8
references.pmid: 10802735
references.citation: Nat Rev Neurosci. 2004 Oct;5(10):771-81
references.pmid: 15378037
references.citation: Biochemistry. 2001 May 22;40(20):5921-30
references.pmid: 11352727
references.citation: J Mol Biol. 2000 Oct 27;303(3):359-70
references.pmid: 11031113
references.citation: Nat Cell Biol. 2006 Nov;8(11):1235-45
references.pmid: 17060907
references.citation: J Biol Chem. 2002 Feb 22;277(8):5699-702
references.pmid: 11741967
references.citation: J Immunol. 2006 Jun 1;176(11):6576-85
references.pmid: 16709815
references.citation: Cold Spring Harb Perspect Biol. 2009 Aug;1(2):a001388
references.pmid: 20066083
references.citation: Cell. 2002 Nov 15;111(4):565-76
references.pmid: 12437929
references.citation: Science. 2008 Oct 17;322(5900):438-42
references.pmid: 18927392
references.citation: Nucleic Acids Res. 2009 Jan;37(Database issue):D229-32
references.pmid: 18978020
references.citation: Cell. 1996 Jun 28;85(7):1067-76
references.pmid: 8674113
references.citation: EMBO J. 2003 Mar 3;22(5):1125-33
references.pmid: 12606577
references.citation: Science. 1999 Oct 8;286(5438):295-9
references.pmid: 10514373
references.citation: Biochemistry. 2010 Feb 9;49(5):951-7
references.pmid: 20047332
references.citation: Science. 1997 Jan 3;275(5296):73-7
references.pmid: 8974395
references.citation: Mol Biol Cell. 2004 Mar;15(3):1324-33
references.pmid: 14718572
references.citation: J Cell Sci. 2001 Sep;114(Pt 18):3219-31
references.pmid: 11591811
references.citation: Nat Cell Biol. 2000 Aug;2(8):540-7
references.pmid: 10934475
references.citation: Bioessays. 1997 Jun;19(6):469-79
references.pmid: 9204764
references.citation: Biomol NMR Assign. 2009 Jun;3(1):45-8
references.pmid: 19636944
references.citation: Nature. 1997 Mar 20;386(6622):279-84
references.pmid: 9069286
references.citation: Curr Biol. 1996 Nov 1;6(11):1385-8
references.pmid: 8939589
references.citation: J Cell Biol. 2007 Mar 12;176(6):863-75
references.pmid: 17353362
references.citation: Biochemistry. 2000 Nov 28;39(47):14638-46
references.pmid: 11087420
references.citation: Nature. 1999 May 27;399(6734):384-8
references.pmid: 10360579
references.citation: J Mol Biol. 2006 Nov 3;363(4):813-22
references.pmid: 16987528
references.citation: J Biomol NMR. 2002 Nov;24(3):171-89
references.pmid: 12522306
references.citation: Science. 2000 Oct 27;290(5492):801-6
references.pmid: 11052943
references.citation: Oncogene. 2008 Nov 24;27(55):6878-87
references.pmid: 19029931
references.citation: Nature. 2000 Mar 9;404(6774):151-8
references.pmid: 10724160