ISSN:
1432-0878
Keywords:
Myofibrils
;
Cytoskeleton
;
Extracellular matrix
;
Laminin
;
Collage
;
Actin filaments
;
Vinculin-Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Neonatal rat cardiomyocytes were cultured on extracellular matrix components laminin and collagens I+III to examine effects of extracellular matrix on the assembly of cytoskeletal proteins during myofibrillogenesis. Myofibril assembly was visualized by immunofluorescence of marker proteins for myofibrils (f-actin for I bands and α-actinin for Z bands), focal adhesions (vinculin), and transmembrane extracellular matrix receptors (β1 integrin) as cells spread for various times in culture. By 4 h in culture, f-actin appeared organized into nonstriated stress-fiber-like structures while α-actinin, vinculin and β1 integrin were localized in small streaks and beads. Subsequently, striated patterns were observed sequentially in the intracellular cytoskeletal components α-actinin, vinculin, f-actin, and then in the transmembrane β1 integrin receptor. These data support an earlier model for sarcomerogenesis in which stress-fiber-like structures serve as initial scaffolds upon which α-actinin and then vinculin-containing costameres are assembled. This sequential and temporal assembly was the same on both laminin and collagens I+III. A quantitative difference, however, was apparent on the 2 matrices. There was an increased appearance on collagens I+III of rosettes (also called podosomes or cortical actin-containing bodies in other cells) which consisted of an f-actin core surrounded by α-actinin, vinculin and β1 integrin rims. The increased incidence of rosettes in neonatal myocytes on collagens I+III suggests that these cytoskeletal complexes are involved in recognition and interaction with extracellular matrix components.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00319047
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