Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2007-7-12
pubmed:abstractText
Isoforms of the smooth muscle myosin motor, SM1 and SM2, differ in length at the carboxy terminal tail region. Their proportion changes with development, hormonal status and disease, but their function is unknown. We developed mice carrying the myosin heavy chain (MyHC) transgenes SM1, cMyc-tagged SM1, SM2, and V5-tagged SM2, and all transgenes corresponded to the SMa NH(2)-terminal isoform. Transgene expression was targeted to smooth muscle by the smooth muscle alpha-actin promoter. Immunoblot analysis showed substantial expression of the cMyc-tagged SM1 and V5-tagged SM2 MyHC protein in aorta and bladder and transgene mRNA was expressed in mice carrying unlabeled SM1 or SM2 transgenes. Despite significant protein expression of tagged MyHCs we found only small changes in the SM1:SM2 protein ratio. Significant changes in functional phenotype were observed in mice carrying unlabeled SM1 or SM2 transgenes. Force in aorta and bladder was increased (72 +/- 14%, 92 +/- 11%) in SM1 and decreased to 57 +/- 1% and 80 +/- 3% in SM2 transgenic mice. SM1 transgenic bladders had faster (1.8 +/- 0.3 s) and SM2 slower (7.1 +/- 0.5 s) rates of force redevelopment following a rapid step shortening. We hypothesize that small changes in the SM1:SM2 ratio could be amplified if they are associated with changes in thick filament assembly and underlie the altered contractility. These data provide evidence indicating an in vivo function for the COOH-terminal isoforms of smooth muscle myosin and suggest that the SM1:SM2 ratio is tightly regulated in smooth muscle tissues.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0363-6143
pubmed:author
pubmed:issnType
Print
pubmed:volume
293
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C238-45
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:17392380-Actins, pubmed-meshheading:17392380-Animals, pubmed-meshheading:17392380-Aorta, pubmed-meshheading:17392380-Dose-Response Relationship, Drug, pubmed-meshheading:17392380-Gene Expression, pubmed-meshheading:17392380-Kinetics, pubmed-meshheading:17392380-Mice, pubmed-meshheading:17392380-Mice, Transgenic, pubmed-meshheading:17392380-Muscle, Smooth, pubmed-meshheading:17392380-Muscle Contraction, pubmed-meshheading:17392380-Muscle Strength, pubmed-meshheading:17392380-Myosin Heavy Chains, pubmed-meshheading:17392380-Phenotype, pubmed-meshheading:17392380-Potassium Chloride, pubmed-meshheading:17392380-Promoter Regions, Genetic, pubmed-meshheading:17392380-Protein Isoforms, pubmed-meshheading:17392380-Protein Structure, Tertiary, pubmed-meshheading:17392380-RNA, Messenger, pubmed-meshheading:17392380-Rats, pubmed-meshheading:17392380-Smooth Muscle Myosins, pubmed-meshheading:17392380-Urinary Bladder
pubmed:year
2007
pubmed:articleTitle
Expression and function of COOH-terminal myosin heavy chain isoforms in mouse smooth muscle.
pubmed:affiliation
Dept. of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Ave., Chicago, IL 60612, USA. afmartin@uic.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural