Magnesium regulates ADP dissociation from myosin V

Steven Rosenfeld, Anne Houdusse, H. Lee Sweeney

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Processivity in myosin V is mediated through the mechanical strain that results when both heads bind strongly to an actin filament, and this strain regulates the timing of ADP release. However, what is not known is which steps that lead to ADP release are affected by this mechanical strain. Answering this question will require determining which of the several potential pathways myosin V takes in the process of ADP release and how actin influences the kinetics of these pathways. We have addressed this issue by examining how magnesium regulates the kinetics of ADP release from myosin V and actomyosin V. Our data support a model in which actin accelerates the release of ADP from myosin V by reducing the magnesium affinity of a myosin V-MgADP intermediate. This is likely a consequence of the structural changes that actin induces in myosin to release phosphate. This effect on magnesium affinity provides a plausible explanation for how mechanical strain can alter this actin-induced acceleration. For actomyosin V, magnesium release follows phosphate release and precedes ADP release. Increasing magnesium concentration to within the physiological range would thus slow both the ATPase activity and the velocity of movement of this motor.

Original languageEnglish (US)
Pages (from-to)6072-6079
Number of pages8
JournalJournal of Biological Chemistry
Volume280
Issue number7
DOIs
StatePublished - Feb 18 2005
Externally publishedYes

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Myosin Type V
Adenosine Diphosphate
Magnesium
Actins
Actomyosin
Phosphates
Myosins
Kinetics
Actin Cytoskeleton
Adenosine Triphosphatases
Head

ASJC Scopus subject areas

  • Biochemistry

Cite this

Magnesium regulates ADP dissociation from myosin V. / Rosenfeld, Steven; Houdusse, Anne; Sweeney, H. Lee.

In: Journal of Biological Chemistry, Vol. 280, No. 7, 18.02.2005, p. 6072-6079.

Research output: Contribution to journalArticle

Rosenfeld, Steven ; Houdusse, Anne ; Sweeney, H. Lee. / Magnesium regulates ADP dissociation from myosin V. In: Journal of Biological Chemistry. 2005 ; Vol. 280, No. 7. pp. 6072-6079.
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