title: Single-molecule force spectroscopy reveals force-enhanced binding of calcium ions by gelsolin.
abstract: Force is increasingly recognized as an important element in controlling biological processes. Forces can deform native protein conformations leading to protein-specific effects. Protein-protein binding affinities may be decreased, or novel protein-protein interaction sites may be revealed, on mechanically stressing one or more components. Here we demonstrate that the calcium-binding affinity of the sixth domain of the actin-binding protein gelsolin (G6) can be enhanced by mechanical force. Our kinetic model suggests that the calcium-binding affinity of G6 increases exponentially with force, up to the point of G6 unfolding. This implies that gelsolin may be activated at lower calcium ion levels when subjected to tensile forces. The demonstration that cation-protein binding affinities can be force-dependent provides a new understanding of the complex behaviour of cation-regulated proteins in stressful cellular environments, such as those found in the cytoskeleton-rich leading edge and at cell adhesions.
authors.affiliation: 1] National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, China [2].
authors.forename: Chunmei
authors.initials: C
authors.lastname: Lv
authors.affiliation: 1] National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, China [2].
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.affiliation: 1] National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, China [2].
authors.forename: Wenfei
authors.initials: W
authors.lastname: Li
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, Singapore 138673, Singapore.
authors.forename: Bo
authors.initials: B
authors.lastname: Xue
authors.affiliation: National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Qin
authors.affiliation: Department of Chemistry and Centre for Blood Research, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: Leslie D
authors.initials: LD
authors.lastname: Burtnick
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
authors.affiliation: National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.affiliation: 1] Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, Singapore 138673, Singapore [2] Department of Biochemistry, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Robinson
authors.affiliation: National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000199:Actins / Q000737:chemistry; D001665:Binding Sites; D001703:Biophysics; D002118:Calcium / Q000737:chemistry*; D002412:Cations; D002448:Cell Adhesion; D018260:Gelsolin / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008840:Microfilament Proteins / Q000378:metabolism; D018625:Microscopy, Atomic Force; D011485:Protein Binding; D011489:Protein Denaturation; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D000199:Actins; D002412:Cations; D018260:Gelsolin; D008024:Ligands; D008840:Microfilament Proteins; D002118:Calcium
references.citation: Proc Natl Acad Sci U S A. 2003 Apr 1;100(7):3942-7
references.pmid: 12655044
references.citation: Biophys J. 2011 Oct 19;101(8):2009-17
references.pmid: 22004755
references.citation: Biophys J. 2012 May 2;102(9):2149-57
references.pmid: 22824279
references.citation: Nature. 2003 May 8;423(6936):190-3
references.pmid: 12736689
references.citation: Cell. 1997 Aug 22;90(4):661-70
references.pmid: 9288746
references.citation: Proc Natl Acad Sci U S A. 2007 Oct 2;104(40):15677-81
references.pmid: 17895384
references.citation: EMBO J. 2004 Jul 21;23(14):2713-22
references.pmid: 15215896
references.citation: Biochemistry. 1995 Feb 7;34(5):1583-8
references.pmid: 7849017
references.citation: Nat Commun. 2010;1:135
references.pmid: 21139580
references.citation: Biophys J. 1999 May;76(5):2439-47
references.pmid: 10233061
references.citation: Biophys J. 2012 Apr 18;102(8):1944-51
references.pmid: 22768951
references.citation: Chemphyschem. 2009 Jul 13;10(9-10):1450-4
references.pmid: 19514035
references.citation: Proc Natl Acad Sci U S A. 2012 Oct 30;109(44):17814-9
references.pmid: 22753517
references.citation: Science. 2009 Jan 30;323(5914):642-4
references.pmid: 19179533
references.citation: J Biol Chem. 2009 Aug 7;284(32):21265-9
references.pmid: 19491107
references.citation: Angew Chem Int Ed Engl. 2006 Jan 16;45(4):642-5
references.pmid: 16345105
references.citation: Science. 2011 Oct 28;334(6055):512-6
references.pmid: 22034433
references.citation: Science. 2011 Dec 23;334(6063):1723-7
references.pmid: 22194581
references.citation: J Biol Chem. 2007 Aug 31;282(35):25884-92
references.pmid: 17604278
references.citation: Biochem J. 2000 Sep 15;350 Pt 3:873-81
references.pmid: 10970804
references.citation: Nat Mater. 2007 Feb;6(2):109-14
references.pmid: 17237787
references.citation: Proc Natl Acad Sci U S A. 2012 Nov 27;109(48):19679-84
references.pmid: 23150587
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):13719-24
references.pmid: 19666531
references.citation: Cell Mol Life Sci. 2004 Oct;61(19-20):2614-23
references.pmid: 15526166
references.citation: Nature. 2003 Mar 27;422(6930):446-9
references.pmid: 12660787
references.citation: Nature. 2010 Nov 25;468(7323):576-9
references.pmid: 21107429
references.citation: Sci Rep. 2014 Apr 09;4:4610
references.pmid: 24714394
references.citation: Science. 1999 Dec 3;286(5446):1939-42
references.pmid: 10583954
references.citation: Science. 1978 May 12;200(4342):618-27
references.pmid: 347575
references.citation: Biotechniques. 1992 Jun;12(6):870-4, 876-9
references.pmid: 1642895
references.citation: J Mol Biol. 2002 Dec 6;324(4):691-702
references.pmid: 12460571
references.citation: Biophys J. 2005 Jul;89(1):506-19
references.pmid: 15863479
references.citation: Science. 1997 May 16;276(5315):1109-12
references.pmid: 9148804
references.citation: Science. 2009 Jan 30;323(5914):638-41
references.pmid: 19179532
references.citation: Physiology (Bethesda). 2013 Jan;28(1):9-17
references.pmid: 23280353
references.citation: Cytoskeleton (Hoboken). 2013 Jul;70(7):360-84
references.pmid: 23749648
references.citation: Cell. 2002 Jun 28;109(7):913-23
references.pmid: 12110187
references.citation: Proc Natl Acad Sci U S A. 2012 Mar 6;109(10):3796-801
references.pmid: 22355138
references.citation: EMBO J. 2001 Nov 15;20(22):6277-87
references.pmid: 11707399
references.citation: J Biol Chem. 2000 Sep 8;275(36):27746-52
references.pmid: 10862770
references.citation: J Biol Chem. 1999 Nov 19;274(47):33179-82
references.pmid: 10559185