title: Structural basis for activation of calcineurin by calmodulin.
abstract: The highly conserved phosphatase calcineurin (CaN) plays vital roles in numerous processes including T-cell activation, development and function of the central nervous system, and cardiac growth. It is activated by the calcium sensor calmodulin (CaM). CaM binds to a regulatory domain (RD) within CaN, causing a conformational change that displaces an autoinhibitory domain (AID) from the active site, resulting in activation of the phosphatase. This is the same general mechanism by which CaM activates CaM-dependent protein kinases. Previously published data have hinted that the RD of CaN is intrinsically disordered. In this work, we demonstrate that the RD is unstructured and that it folds upon binding CaM, ousting the AID from the catalytic site. The RD is 95 residues long, with the AID attached to its C-terminal end and the 24-residue CaM binding region toward the N-terminal end. This is unlike the CaM-dependent protein kinases that have CaM binding sites and AIDs immediately adjacent in sequence. Our data demonstrate that not only does the CaM binding region folds but also an ∼25- to 30-residue region between it and the AID folds, resulting in over half of the RD adopting α-helical structure. This appears to be the first observation of CaM inducing folding of this scale outside of its binding site on a target protein.
authors.affiliation: Center for Structural Biology, Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Rumi-Masante
authors.forename: Farai I
authors.initials: FI
authors.lastname: Rusinga
authors.forename: Terrence E
authors.initials: TE
authors.lastname: Lester
authors.forename: Tori B
authors.initials: TB
authors.lastname: Dunlap
authors.forename: Todd D
authors.initials: TD
authors.lastname: Williams
authors.forename: A Keith
authors.initials: AK
authors.lastname: Dunker
authors.forename: David D
authors.initials: DD
authors.lastname: Weis
authors.forename: Trevor P
authors.initials: TP
authors.lastname: Creamer
mesh_terms: D000595:Amino Acid Sequence; D019703:Calcineurin / Q000737:chemistry* / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism*; D002942:Circular Dichroism; D006801:Humans; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary
chemical_list: D002147:Calmodulin; D019703:Calcineurin
references.citation: Physiol Rev. 2000 Oct;80(4):1483-521
references.pmid: 11015619
references.citation: Biochemistry. 2011 Oct 11;50(40):8722-32
references.pmid: 21894929
references.citation: Biochemistry. 1978 Jan 10;17(1):120-6
references.pmid: 201280
references.citation: J Biol Chem. 2001 Oct 19;276(42):38787-94
references.pmid: 11483593
references.citation: Methods Enzymol. 1983;102:17-39
references.pmid: 6645969
references.citation: Biochemistry. 2000 Dec 26;39(51):16147-54
references.pmid: 11123943
references.citation: Anal Biochem. 1985 Oct;150(1):76-85
references.pmid: 3843705
references.citation: Anal Biochem. 2000 Dec 15;287(2):252-60
references.pmid: 11112271
references.citation: Arch Biochem Biophys. 1999 Dec 1;372(1):159-65
references.pmid: 10562429
references.citation: Proteins. 2006 May 1;63(2):398-410
references.pmid: 16493654
references.citation: Protein Sci. 1993 Apr;2(4):522-31
references.pmid: 8390883
references.citation: Biochemistry. 1989 Feb 21;28(4):1868-74
references.pmid: 2541767
references.citation: Biochemistry. 1994 Jun 7;33(22):6859-66
references.pmid: 8204620
references.citation: Genome Inform Ser Workshop Genome Inform. 1997;8:110-124
references.pmid: 11072311
references.citation: J Biol Chem. 1990 Feb 5;265(4):1924-7
references.pmid: 2153670
references.citation: Cell Mol Life Sci. 2008 Sep;65(17):2637-57
references.pmid: 18463790
references.citation: Biophys J. 2007 Mar 1;92(5):1439-56
references.pmid: 17158572
references.citation: J Neurosci. 2007 Nov 28;27(48):13161-72
references.pmid: 18045910
references.citation: J Biol Chem. 2008 Apr 25;283(17):11407-13
references.pmid: 18296442
references.citation: J Biol Chem. 2003 Sep 26;278(39):36981-4
references.pmid: 12881512
references.citation: Biochemistry. 1981 Jan 6;20(1):33-7
references.pmid: 7470476
references.citation: Mol Cell Proteomics. 2002 Feb;1(2):132-8
references.pmid: 12096131
references.citation: Curr Opin Struct Biol. 2002 Feb;12(1):54-60
references.pmid: 11839490
references.citation: Mol Cell Biochem. 2007 Apr;298(1-2):1-40
references.pmid: 17119849
references.citation: J Am Chem Soc. 2006 Jun 21;128(24):7772-81
references.pmid: 16771491
references.citation: J Biol Chem. 1998 May 29;273(22):13367-70
references.pmid: 9593662
references.citation: Proteins. 2011 Mar;79(3):765-86
references.pmid: 21287611
references.citation: Anal Biochem. 2010 Apr 15;399(2):237-45
references.pmid: 20036207
references.citation: J Biol Chem. 1995 Jan 6;270(1):340-6
references.pmid: 7814394
references.citation: Biochem Biophys Res Commun. 1976 Nov 8;73(1):40-6
references.pmid: 187190
references.citation: Biochem Biophys Res Commun. 2005 Aug 26;334(2):674-80
references.pmid: 16009337
references.citation: Genome Biol. 2005;6(7):226
references.pmid: 15998457
references.citation: Nature. 1995 Dec 7;378(6557):641-4
references.pmid: 8524402
references.citation: J Am Soc Mass Spectrom. 2011 Aug;22(8):1472-6
references.pmid: 21953202
references.citation: Proc Natl Acad Sci U S A. 1983 Jul;80(14):4291-5
references.pmid: 6576338
references.citation: J Mol Graph Model. 2001;19(1):26-59
references.pmid: 11381529
references.citation: Biochem Biophys Res Commun. 1976 Oct 4;72(3):926-32
references.pmid: 186066