title: Rigidity of collagen fibrils controls collagen gel-induced down-regulation of focal adhesion complex proteins mediated by alpha2beta1 integrin.
abstract: Previous studies have shown that collagen gel overlay induced selective proteolysis of focal adhesion complex proteins in Madin-Darby canine kidney (MDCK) cells. In this study, we examined whether morphological and biochemical changes were present in cells cultured on collagen gel. We found that focal adhesion complex proteins, including focal adhesion kinase (FAK), talin, paxillin, and p130cas, but not vinculin, were decreased within 1 h when MDCK cells were cultured on collagen gel. Collagen gel-induced selective decrease of focal adhesion proteins was observed in all lines of cells examined, including epithelial, fibroblastic, and cancer cells. Matrigel also induced selective down-regulation of focal adhesion proteins. However, cells cultured on collagen gel- or matrigel-coated dishes did not show any changes of focal adhesion proteins. These data suggest that the physical nature of the gel, i.e. the rigidity, is involved in the expression of focal adhesion proteins. The collagen gel-induced down-regulation of focal adhesion complex proteins was caused by reduction of protein synthesis and activation of proteases such as calpain. Overexpression of a dominant negative mutant of discoidin domain receptor 1 (DDR1) or FAK-related non-kinase (FRNK) did not prevent collagen gel-induced down-regulation of the focal adhesion complex protein, whereas an anti-alpha2beta1 integrin-neutralizing antibody completely blocked it. Taken together, our results indicate that the rigidity of collagen gel controls the expression of focal adhesion complex proteins, which is mediated by alpha2beta1 integrin but not DDR1.
authors.affiliation: Institute of Basic Medical Sciences, National Cheng-Kung University Medical College, Tainan 701, Taiwan, Republic of China.
authors.forename: Yang-Kao
authors.initials: YK
authors.lastname: Wang
authors.forename: Yao-Hsien
authors.initials: YH
authors.lastname: Wang
authors.forename: Chau-Zen
authors.initials: CZ
authors.lastname: Wang
authors.forename: Junne-Ming
authors.initials: JM
authors.lastname: Sung
authors.forename: Wen-Tai
authors.initials: WT
authors.lastname: Chiu
authors.forename: Shu-Han
authors.initials: SH
authors.lastname: Lin
authors.forename: Yung-Hen
authors.initials: YH
authors.lastname: Chang
authors.forename: Ming-Jer
authors.initials: MJ
authors.lastname: Tang
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D002154:Calpain / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins / Q000378:metabolism; D000070819:Discoidin Domain Receptor 1; D004285:Dogs; D015536:Down-Regulation; D004338:Drug Combinations; D022001:Focal Adhesions; D006367:HeLa Cells; D006801:Humans; D038982:Integrin alpha2beta1 / Q000378:metabolism*; D007797:Laminin / Q000494:pharmacology; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism; D011506:Proteins; D011509:Proteoglycans / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012685:Sepharose / Q000494:pharmacology; D016608:Talin / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: C493841:BCAR1 protein, human; C493842:Bcar1 protein, mouse; C493843:Bcar1 protein, rat; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins; D004338:Drug Combinations; D038982:Integrin alpha2beta1; D007797:Laminin; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; D011509:Proteoglycans; C496062:Pxn protein, mouse; C496063:Pxn protein, rat; D050717:Retinoblastoma-Like Protein p130; D016608:Talin; C059485:matrigel; D003094:Collagen; D012685:Sepharose; C092030:DDR1 protein, human; D000070819:Discoidin Domain Receptor 1; D020794:Receptor Protein-Tyrosine Kinases; D002154:Calpain