Myofibrillar and cytoskeletal assembly in neonatal rat cardiac myocytes cultured on laminin and collagen

Lula L. Hilenski, Louis Terracio, Thomas K. Borg

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Pages (from-to)577-587
Number of pages11
JournalCell and Tissue Research
Volume264
Issue number3
DOIs
StatePublished - Jun 1991

Keywords

  • Actin filaments
  • Collage
  • Cytoskeleton
  • Extracellular matrix
  • Laminin
  • Myofibrils
  • Vinculin-Rat

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology

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