Linked Life Data

11771963

Source:http://linkedlifedata.com/resource/pubmed/id/11771963

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-1-4
pubmed:abstractText
The vertebrate muscle Z-band organizes and tethers antiparallel actin filaments in adjacent sarcomeres and hence propagates the tension generated by the actomyosin interaction during muscular contraction. The axial width of the Z-band varies with fibre and muscle type: fast twitch muscles have narrow (approximately 30-50 nm) Z-bands, while slow-twitch and cardiac muscles have wide (approximately 100-140 nm) Z-bands. In electron micrographs of longitudinal sections of fast fibres like those found in fish body white muscle, the Z-band appears as a characteristic zigzag layer of density connecting the mutually offset actin filament arrays in adjacent sarcomeres. Wide Z-bands in slow fibres such as the one studied here (bovine neck muscle) show a stack of three or four zigzag layers. The variable Z-band width incorporating variable numbers of zigzag layers presumably relates to the different mechanical properties of the respective muscles. Three-dimensional reconstructions of Z-bands reveal that individual zigzag layers are often composed of more than one set of protein bridges, called Z-links, probably alpha-actinin, between oppositely oriented actin filaments. Fast muscle Z-bands comprise two or three layers of Z-links. Here we have applied Fourier reconstruction methods to obtain clear three-dimensional density maps of the Z-bands in beef muscle. The bovine slow muscle investigated here reveals a Z-band comprising six sets of Z-links, which, due to their shape and the way their projected densities overlap, appear in longitudinal sections as either three or four zigzag layers, depending on the lattice view. There has been great interest recently in the suggestion that Z-band variability with fibre type may be due to differences in the repetitive region (tandem Z-repeats) in the Z-band part of titin (also called connectin). We discuss this in the context of our results and present a systematic classification of Z-band types according to the numbers of Z-links and titin Z-repeats.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Academic Press.
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
315
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9-20
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
The three-dimensional structure of a vertebrate wide (slow muscle) Z-band: lessons on Z-band assembly.
pubmed:affiliation
Biological Structure and Function Section, Biomedical Sciences Division, Faculty of Medicine, Imperial College, Exhibition Road, London, SW7 2AZ, UK. p.luther@ic.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't