Tension is required for fibripositor formation

Zoher Kapacee, Susan H. Richardson, Yinhui Lu, Tobias Starborg, David F. Holmes, Keith Baar, Karl E. Kadler

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


Embryonic tendon cells (ETCs) have actin-rich fibripositors that accompany parallel bundles of collagen fibrils in the extracellular matrix. To study fibripositor function, we have developed a three-dimensional cell culture system that promotes and maintains fibripositors. We show that ETCs cultured in fixed-length fibrin gels replace the fibrin during ~ 6 days in culture with parallel bundles of narrow-diameter collagen fibrils that are uniaxially aligned with fibripositors, thereby generating a tendon-like construct. Fibripositors occurred simultaneously with onset of parallel collagen fibrils. Interestingly, the constructs have a tendon-like crimp. In initial experiments to study the effects of tension, we showed that cutting the constructs resulted in loss of tension, loss of fibripositors and the appearance of immature fibrils with no preferred orientation.

Original languageEnglish (US)
Pages (from-to)371-375
Number of pages5
JournalMatrix Biology
Issue number4
StatePublished - May 2008
Externally publishedYes


  • Aligned
  • Axial
  • Collagen fibrils
  • Embryonic tendon cells
  • Fibrin
  • Parallel

ASJC Scopus subject areas

  • Molecular Biology


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