Low substratum rigidity of collagen gel promotes ERK phosphorylation via lipid raft to augment cell migration
✍ Scribed by Wei-Chun Wei; Yu-Chih Hsu; Wen-Tai Chiu; Chau-Zen Wang; Ching-Ming Wu; Yang-Kao Wang; Meng-Ru Shen; Ming-Jer Tang
- Book ID
- 102301483
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 464 KB
- Volume
- 103
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Abstract
Previous study demonstrated that low substratum rigidity down‐regulates focal adhesion proteins. In this study we found that cells cultured on collagen gel exhibited higher migration capacity than those cultured on collagen gel‐coated dishes. Low rigidity of collagen gel induced delayed but persistent phosphorylation of ERK1/2. Inhibition of collagen gel‐induced ERK1/2 phosphorylation by MEK inhibitors and ERK2 kinase mutant induced a rounding up of the cells and prevented collagen gel‐induced cell migration. Interestingly, phosphorylated ERK1/2 induced by low rigidity was present in focal adhesion sites and the lipid raft. MβCD (Methyl‐β‐cyclodextrin), a lipid raft inhibitor, inhibited collagen gel‐induced ERK1/2 phosphorylation, and cell migration. Overexpression of FAK C‐terminal fragment (FRNK) in MDCK cells triggered ERK phosphorylation. Meanwhile, low substratum rigidity induced degradation of FAK into a 35 kDa C‐terminal fragment. A calpain inhibitor that partially rescued FAK degradation also prevented low rigidity‐induced ERK phosphorylation. However, MβCD did not prevent low rigidity‐induced FAK degradation. Taken together, we demonstrate that the degradation product of FAK induced by collagen gel triggers activation of ERK1/2, which in turn facilitates cell spreading and migration through the lipid raft. J. Cell. Biochem. 103: 1111–1124, 2008. © 2007 Wiley‐Liss, Inc.