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Nat Struct Mol Biol. 2005 Feb;12(2):127-32. Epub 2005 Jan 23.

Motility of myosin V regulated by the dissociation of single calmodulin.

Author information

1
Center for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan.

Abstract

Myosin V is a calmodulin-binding motor protein. The dissociation of single calmodulin molecules from individual myosin V molecules at 1 microM Ca(2+) correlates with a reduction in sliding velocity in an in vitro motility assay. The dissociation of two calmodulin molecules at 5 microM Ca(2+) correlates with a detachment of actin filaments from myosin V. To mimic the regulation of myosin V motility by Ca(2+) in a cell, caged Ca(2+) coupled with a UV flash system was used to produce Ca(2+) transients. During the Ca(2+) transient, myosin V goes through the functional cycle of reduced sliding velocity, actin detachment and reattachment followed by the recovery of the sliding velocity. These results indicate that myosin V motility is regulated by Ca(2+) through a reduction in actin-binding affinity resulting from the dissociation of single calmodulin molecules.

PMID:
15665867
DOI:
10.1038/nsmb894
[Indexed for MEDLINE]

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