α-smooth muscle actin is crucial for focal adhesion maturation in myofibroblasts

被引:244
作者
Hinz, B [1 ]
Dugina, V
Ballestrem, C
Wehrle-Haller, B
Chaponnier, C
机构
[1] Univ Geneva, Ctr Med Univ, Dept Pathol, CH-1211 Geneva 4, Switzerland
[2] Moscow MV Lomonosov State Univ, Moscow 119899, Russia
[3] Weizmann Inst Sci, Dept Mol Cell Biol, IL-76100 Rehovot, Israel
关键词
D O I
10.1091/mbc.E02-11-0729
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Cultured myofibroblasts are characterized by stress fibers, containing alpha-smooth muscle actin (alpha-SMA) and by supermature focal adhesions (FAs), which are larger than FAs of alpha-SMA-negative fibroblasts. We have investigated the role of alpha-SMA for myofibroblast adhesion and FA maturation. Inverted centrifugation reveals two phases of initial myofibroblast attachment: during the first 2 h of plating microfilament bundles contain essentially cytoplasmic actin and myofibroblast adhesion is similar to that of alpha-SMA-negative fibroblasts. Then, myofibroblasts incorporate alpha-SMA in stress fibers, develop mature FAs and their adhesion capacity is significantly increased. When alpha-SMA, expression is induced in 5 d culture by TGFbeta or low serum levels, fibroblast adhesion is further increased correlating with a "supermaturation" of FAs. Treatment of myofibroblasts with alpha-SMA fusion peptide (SMA-FP), which inhibits alpha-SMA-mediated contractile activity, reduces their adhesion to the level of alpha-SMA negative fibroblasts. With the use of flexible micropatterned substrates and EGFP-constructs we show that SMA-FP application leads to a decrease of myofibroblast contraction, shortly followed by disassembly of paxillin- and beta3 integrin-containing FAs; alpha5 integrin distribution is, not affected. FRAP of beta3 integrin-EGFP demonstrates an increase of FA protein turnover following SMA-FP treatment. We conclude that the formation and stability of supermature FAs depends on a high alpha-SMA-mediated contractile activity of myofibroblast stress fibers.
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页码:2508 / 2519
页数:12
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