title: The C-terminal calcium-sensitive disordered motifs regulate isoform-specific polymerization characteristics of calsequestrin.
abstract: Calsequestrin (CASQ) exists as two distinct isoforms CASQ1 and CASQ2 in all vertebrates. Although the isoforms exhibit unique functional characteristic, the structural basis for the same is yet to be fully defined. Interestingly, the C-terminal region of the two isoforms exhibit significant differences both in length and amino acid composition; forming Dn-motif and DEXn-motif in CASQ1 and CASQ2, respectively. Here, we investigated if the unique C-terminal motifs possess Ca(2+)-sensitivity and affect protein function. Sequence analysis shows that both the Dn- and DEXn-motifs are intrinsically disordered regions (IDRs) of the protein, a feature that is conserved from fish to man. Using purified synthetic peptides, we show that these motifs undergo distinctive Ca(2+)-mediated folding suggesting that these disordered motifs are Ca(2+)-sensitivity. We generated chimeric proteins by swapping the C-terminal portions between CASQ1 and CASQ2. Our studies show that the C-terminal portions do not play significant role in protein folding. An interesting finding of the current study is that the switching of the C-terminal portion completely reverses the polymerization kinetics. Collectively, these data suggest that these Ca(2+)-sensitivity IDRs located at the back-to-back dimer interface influence isoform-specific Ca(2+)-dependent polymerization properties of CASQ.
authors.affiliation: Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210.
authors.forename: Naresh C
authors.initials: NC
authors.lastname: Bal
authors.forename: Nivedita
authors.initials: N
authors.lastname: Jena
authors.forename: Harapriya
authors.initials: H
authors.lastname: Chakravarty
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.forename: Mei
authors.initials: M
authors.lastname: Chi
authors.forename: Tuniki
authors.initials: T
authors.lastname: Balaraju
authors.forename: Sharad V
authors.initials: SV
authors.lastname: Rawale
authors.forename: Jayashree S
authors.initials: JS
authors.lastname: Rawale
authors.forename: Ashoke
authors.initials: A
authors.lastname: Sharon
authors.forename: Muthu
authors.initials: M
authors.lastname: Periasamy
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D002155:Calsequestrin / Q000737:chemistry*; D002942:Circular Dichroism; D058105:Polymerization; D020033:Protein Isoforms / Q000737:chemistry*; D017434:Protein Structure, Tertiary
chemical_list: D002135:Calcium-Binding Proteins; D002155:Calsequestrin; D020033:Protein Isoforms; D002118:Calcium
keywords: calcium binding protein; calcium-induced polymerization; circular dichroism; disordered motifs
references.citation: Exp Cell Res. 2009 Feb 1;315(3):523-34
references.pmid: 19059396
references.citation: J Mol Graph. 1996 Feb;14(1):33-8, 27-8
references.pmid: 8744570
references.citation: Biol Chem. 2007 May;388(5):467-79
references.pmid: 17516842
references.citation: J Cell Biol. 2001 Aug 6;154(3):525-34
references.pmid: 11489915
references.citation: J Biol Chem. 2010 Jan 29;285(5):3076-83
references.pmid: 19920148
references.citation: J Theor Biol. 2008 Aug 21;253(4):668-79
references.pmid: 18538346
references.citation: Exp Cell Res. 2006 Dec 10;312(20):4150-61
references.pmid: 17045261
references.citation: Biochem J. 1999 Jan 1;337 ( Pt 1):19-22
references.pmid: 9854019
references.citation: J Biol Chem. 2003 May 2;278(18):16176-82
references.pmid: 12594204
references.citation: Structure. 2003 Nov;11(11):1453-9
references.pmid: 14604535
references.citation: Am J Physiol. 1992 Mar;262(3 Pt 1):C614-20
references.pmid: 1372478
references.citation: Cell Mol Life Sci. 2013 Aug;70(16):2935-45
references.pmid: 23109100
references.citation: Cell Calcium. 2009 May;45(5):474-84
references.pmid: 19376574
references.citation: Am J Physiol. 1999 Nov;277(5):C974-81
references.pmid: 10564090
references.citation: Comp Biochem Physiol B Biochem Mol Biol. 2011 Apr;158(4):304-14
references.pmid: 21256971
references.citation: PLoS One. 2012;7(11):e50801
references.pmid: 23226387
references.citation: Biochem J. 2011 Apr 15;435(2):391-9
references.pmid: 21265816
references.citation: Biophys J. 2004 Apr;86(4):2121-8
references.pmid: 15041652
references.citation: Exp Cell Res. 2001 Apr 15;265(1):104-13
references.pmid: 11281648
references.citation: FEBS Lett. 1989 Jan 2;242(2):297-300
references.pmid: 2914612
references.citation: Gene. 1991 Dec 30;109(2):275-9
references.pmid: 1662658
references.citation: J Muscle Res Cell Motil. 1990 Dec;11(6):522-30
references.pmid: 2084148
references.citation: J Biol Chem. 1991 Jan 5;266(1):391-8
references.pmid: 1985907
references.citation: J Biol Chem. 1988 Jun 25;263(18):8958-64
references.pmid: 3379055
references.citation: Biochim Biophys Acta. 2010 Apr;1804(4):996-1010
references.pmid: 20100603
references.citation: Exp Cell Res. 2000 Oct 10;260(1):40-9
references.pmid: 11010809
references.citation: J Cell Sci. 2007 May 1;120(Pt 9):1551-8
references.pmid: 17405817
references.citation: Biophys J. 2008 Oct;95(8):3767-89
references.pmid: 18676655
references.citation: J Comput Chem. 2005 Dec;26(16):1781-802
references.pmid: 16222654
references.citation: Biopolymers. 2000-2001;56(4):257-65
references.pmid: 11754339
references.citation: Mol Biosyst. 2013 Jul;9(7):1949-57
references.pmid: 23629537
references.citation: Proteins. 2005;61 Suppl 7:176-82
references.pmid: 16187360
references.citation: J Biol Chem. 2010 May 28;285(22):17188-96
references.pmid: 20353949
references.citation: Bioinformatics. 2005 Aug 15;21(16):3433-4
references.pmid: 15955779
references.citation: FEBS Lett. 1992 Mar 9;299(2):175-8
references.pmid: 1544490
references.citation: J Physiol. 2009 Jan 15;587(2):443-60
references.pmid: 19029185
references.citation: J Gen Physiol. 2010 Sep;136(3):325-38
references.pmid: 20713548
references.citation: Biophys J. 2009 Oct 7;97(7):1961-70
references.pmid: 19804727
references.citation: J Biol Chem. 2012 Mar 30;287(14):11592-601
references.pmid: 22337878
references.citation: Prog Biophys Mol Biol. 2004 May;85(1):33-69
references.pmid: 15050380
references.citation: Am J Physiol. 1997 May;272(5 Pt 1):C1420-8
references.pmid: 9176130
references.citation: J Biol Chem. 2004 Apr 23;279(17):18026-33
references.pmid: 14871888
references.citation: Biochim Biophys Acta. 2000 Jun 1;1466(1-2):151-68
references.pmid: 10825439
references.citation: Gene. 1998 Sep 14;217(1-2):25-30
references.pmid: 9795116
references.citation: Cell Calcium. 2003 May-Jun;33(5-6):375-84
references.pmid: 12765683
references.citation: Am J Physiol Heart Circ Physiol. 2011 Feb;300(2):H595-604
references.pmid: 21131479
references.citation: Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2982-7
references.pmid: 16473932
references.citation: J Biol Chem. 1974 Apr 25;249(8):2357-65
references.pmid: 4856651