Document Detail


Kinetic mechanism of non-muscle myosin IIB: functional adaptations for tension generation and maintenance.
MedLine Citation:
PMID:  12704189     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Besides driving contraction of various types of muscle tissue, conventional (class II) myosins serve essential cellular functions and are ubiquitously expressed in eukaryotic cells. Three different isoforms in the human myosin complement have been identified as non-muscle class II myosins. Here we report the kinetic characterization of a human non-muscle myosin IIB subfragment-1 construct produced in the baculovirus expression system. Transient kinetic data show that most steps of the actomyosin ATPase cycle are slowed down compared with other class II myosins. The ADP affinity of subfragment-1 is unusually high even in the presence of actin filaments, and the rate of ADP release is close to the steady-state ATPase rate. Thus, non-muscle myosin IIB subfragment-1 spends a significantly higher proportion of its kinetic cycle strongly attached to actin than do the muscle myosins. This feature is even more pronounced at slightly elevated ADP levels, and it may be important in carrying out the cellular functions of this isoform working in small filamentous assemblies.
Authors:
Fei Wang; Mihaly Kovacs; Aihua Hu; John Limouze; Estelle V Harvey; James R Sellers
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Publication Detail:
Type:  Journal Article     Date:  2003-04-17
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  278     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-21     Completed Date:  2003-08-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  27439-48     Citation Subset:  IM    
Affiliation:
Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1762, USA.
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MeSH Terms
Descriptor/Qualifier:
Actins / chemistry
Actomyosin / chemistry
Adenosine Diphosphate / chemistry
Adenosine Triphosphatases / chemistry
Adenosine Triphosphate / chemistry,  metabolism,  pharmacology
Animals
Cloning, Molecular
DNA, Complementary / metabolism
Dose-Response Relationship, Drug
Humans
Hydrolysis
Kinetics
Models, Chemical
Nonmuscle Myosin Type IIB / chemistry*
Phosphorylation
Protein Isoforms
Pyrenes / chemistry
Rabbits
Thermodynamics
Time Factors
Chemical
Reg. No./Substance:
0/Actins; 0/DNA, Complementary; 0/Protein Isoforms; 0/Pyrenes; 129-00-0/pyrene; 56-65-5/Adenosine Triphosphate; 58-64-0/Adenosine Diphosphate; 9013-26-7/Actomyosin; EC 3.6.1.-/Adenosine Triphosphatases; EC 3.6.1.-/Nonmuscle Myosin Type IIB

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


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