Activation of pp60(src) is critical for stretch-induced orienting response in fibroblasts

Xiaorui Sai, Keiji Naruse, Masahiro Sokabe

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76 Citations (Scopus)


When subjected to uni-axial cyclic stretch (120% in length, 1 Hz), fibroblasts (3Y1) aligned perpendicular to the stretch axis in a couple of hours. Concomitantly with this orienting response, protein tyrosine phosphorylation of cellular proteins (molecular masses of approximately 70 kDa and 120-130 kDa) increased and peaked at 30 minutes. Immuno-precipitation experiments revealed that paxillin, pp125(FAK), and pp30(CAS) were included in the 70 kDa, and 120-130 kDa bands, respectively. Treatment of the cells with herbimycin A, a tyrosine kinase inhibitor, suppressed the stretch induced tyrosine phosphorylation and the orienting response suggesting that certain tyrosine kinases are activated by stretch. We focused on pp60(src), the most abundant tyrosine kinase in fibroblasts. The kinase activity of pp60(src) increased and peaked at 20 minutes after the onset of cyclic stretch. Treatment of the cells with an antisense S-oligodeoxynucleotide (S-ODN) against pp60(src), but not the sense S-ODN, inhibited the stretch induced tyrosine phosphorylation and the orienting response. To further confirm the involvement of pp60(src), we performed the same sets of experiments using c-src-transformed 3Y1 (c-src-3Y1) fibroblasts. Cyclic stretch induced a similar orienting response in c-src-3Y1 to that in wild-type 3Y1, but with a significantly faster rate. The time course of the stretch-induced tyrosine phosphorylation was also much faster in c-src-3Y1 than in 3Y1 fibroblasts. These results strongly suggest that cyclic stretch induces the activation of pp60(src) and that pp60(src) is indispensable for the phosphorylation of pp130(CAS), pp125(FAK) and paxillin followed by the orienting response in 3Y1 fibroblasts.

Original languageEnglish
Pages (from-to)1365-1373
Number of pages9
JournalJournal of cell science
Issue number9
Publication statusPublished - Jun 5 1999
Externally publishedYes


  • Ca
  • Gd
  • Protein tyrosine phosphorylation
  • Uni-axial cyclic stretch
  • c-src transformed 3Y1 fibroblast

ASJC Scopus subject areas

  • Cell Biology


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