Document Detail


Myosin IC generates power over a range of loads via a new tension-sensing mechanism.
MedLine Citation:
PMID:  22908250     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Myosin IC (myo1c), a widely expressed motor protein that links the actin cytoskeleton to cell membranes, has been associated with numerous cellular processes, including insulin-stimulated transport of GLUT4, mechanosensation in sensory hair cells, endocytosis, transcription of DNA in the nucleus, exocytosis, and membrane trafficking. The molecular role of myo1c in these processes has not been defined, so to better understand myo1c function, we utilized ensemble kinetic and single-molecule techniques to probe myo1c's biochemical and mechanical properties. Utilizing a myo1c construct containing the motor and regulatory domains, we found the force dependence of the actin-attachment lifetime to have two distinct regimes: a force-independent regime at forces < 1 pN, and a highly force-dependent regime at higher loads. In this force-dependent regime, forces that resist the working stroke increase the actin-attachment lifetime. Unexpectedly, the primary force-sensitive transition is the isomerization that follows ATP binding, not ADP release as in other slow myosins. This force-sensing behavior is unique amongst characterized myosins and clearly demonstrates mechanochemical diversity within the myosin family. Based on these results, we propose that myo1c functions as a slow transporter rather than a tension-sensitive anchor.
Authors:
Michael J Greenberg; Tianming Lin; Yale E Goldman; Henry Shuman; E Michael Ostap
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-08-20
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  109     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-09-12     Completed Date:  2012-12-10     Revised Date:  2014-03-19    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E2433-40     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Actins / physiology*
Adenosine Diphosphate / metabolism
Adenosine Triphosphate / metabolism
Animals
Biomechanical Phenomena
Calmodulin / metabolism
Carrier Proteins / physiology*
Chromatography, Liquid
Likelihood Functions
Mice
Muscle Tonus / physiology*
Myosin Type I / physiology*
Optical Tweezers
Grant Support
ID/Acronym/Agency:
F32 GM097889/GM/NIGMS NIH HHS; P01 GM087253/GM/NIGMS NIH HHS; P01 GM087253/GM/NIGMS NIH HHS; T32 AR053461/AR/NIAMS NIH HHS; T32 AR053461/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
0/Actins; 0/Calmodulin; 0/Carrier Proteins; 0/Myo1c protein, mouse; 61D2G4IYVH/Adenosine Diphosphate; 8L70Q75FXE/Adenosine Triphosphate; EC 3.6.1.-/Myosin Type I
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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