title: Millisecond-scale biochemical response to change in strain.
abstract: Muscle fiber contraction involves the cyclical interaction of myosin cross-bridges with actin filaments, linked to hydrolysis of ATP that provides the required energy. We show here the relationship between cross-bridge states, force generation, and Pi release during ramp stretches of active mammalian skeletal muscle fibers at 20°C. The results show that force and Pi release respond quickly to the application of stretch: force rises rapidly, whereas the rate of Pi release decreases abruptly and remains low for the duration of the stretch. These measurements show that biochemical change on the millisecond timescale accompanies the mechanical and structural responses in active muscle fibers. A cross-bridge model is used to simulate the effect of stretch on the distribution of actomyosin cross-bridges, force, and Pi release, with explicit inclusion of ATP, ADP, and Pi in the biochemical states and length-dependence of transitions. In the simulation, stretch causes rapid detachment and reattachment of cross-bridges without release of Pi or ATP hydrolysis.
authors.affiliation: Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, United Kingdom.
authors.forename: Dale C
authors.initials: DC
authors.lastname: Bickham
authors.forename: Timothy G
authors.initials: TG
authors.lastname: West
authors.forename: Martin R
authors.initials: MR
authors.lastname: Webb
authors.forename: Roger C
authors.initials: RC
authors.lastname: Woledge
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Curtin
authors.forename: Michael A
authors.initials: MA
authors.lastname: Ferenczi
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D003198:Computer Simulation; D005453:Fluorescence; D007537:Isometric Contraction / Q000502:physiology; D007700:Kinetics; D008954:Models, Biological; D010710:Phosphates; D011817:Rabbits; D013314:Stress, Mechanical; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D010710:Phosphates; D000205:Actomyosin
references.citation: Adv Exp Med Biol. 1998;453:331-41
references.pmid: 9889845
references.citation: Biochemistry. 1971 Dec 7;10(25):4617-24
references.pmid: 4258719
references.citation: J Physiol. 1991 Jun;437:63-70
references.pmid: 1890652
references.citation: J Physiol. 2006 Jun 15;573(Pt 3):627-43
references.pmid: 16627571
references.citation: Prog Biophys Mol Biol. 1974;28:267-340
references.pmid: 4617248
references.citation: J Physiol. 1997 May 15;501 ( Pt 1):125-48
references.pmid: 9174999
references.citation: Biophys J. 1990 Feb;57(2):209-21
references.pmid: 2317547
references.citation: J Physiol. 2003 Apr 15;548(Pt 2):461-74
references.pmid: 12598584
references.citation: J Physiol. 2004 Jan 15;554(Pt 2):335-52
references.pmid: 14555725
references.citation: J Physiol. 1939 Jun 14;96(1):45-64
references.pmid: 16995114
references.citation: Proc Natl Acad Sci U S A. 2007 Dec 11;104(50):20114-9
references.pmid: 18077437
references.citation: J Physiol. 1992 Jan;445:659-711
references.pmid: 1501149
references.citation: J Appl Physiol (1985). 2010 Jun;108(6):1465-71
references.pmid: 20133436
references.citation: Biophys J. 2006 May 15;90(10):3653-65
references.pmid: 16513783
references.citation: J Physiol. 1994 Mar 15;475(3):483-94
references.pmid: 8006830
references.citation: J Mechanochem Cell Motil. 1975;3(2):147-54
references.pmid: 1082485
references.citation: J Exp Biol. 2002 May;205(Pt 9):1275-83
references.pmid: 11948204
references.citation: Biophys J. 1989 Aug;56(2):429-33
references.pmid: 2789080
references.citation: Proc R Soc Lond B Biol Sci. 1978 May 5;201(1143):107-30
references.pmid: 27795
references.citation: J Physiol. 1978 Mar;276:467-79
references.pmid: 306434
references.citation: Prog Biophys Biophys Chem. 1957;7:255-318
references.pmid: 13485191
references.citation: J Physiol. 1990 Dec;431:141-71
references.pmid: 2100305
references.citation: J Physiol. 1978 Aug;281:139-55
references.pmid: 309001
references.citation: Biochemistry. 1994 Jul 12;33(27):8262-71
references.pmid: 8031761
references.citation: Nature. 1971 Oct 22;233(5321):533-8
references.pmid: 4939977
references.citation: Proc Natl Acad Sci U S A. 2003 Nov 11;100(23):13716-21
references.pmid: 14593205
references.citation: J Physiol. 1999 Jun 15;517 ( Pt 3):839-54
references.pmid: 10358123
references.citation: Biophys J. 2009 Apr 22;96(8):3281-94
references.pmid: 19383472
references.citation: Biophys J. 1998 Nov;75(5):2389-401
references.pmid: 9788934
references.citation: Adv Exp Med Biol. 2003;538:613-25; discussion 625-6
references.pmid: 15098703
references.citation: Biophys J. 1998 Dec;75(6):2971-83
references.pmid: 9826617
references.citation: J Physiol. 1997 Nov 15;505 ( Pt 1):205-15
references.pmid: 9409483