Aortic smooth muscle cells interact with tenascin-C through its fibrinogen-like domain.
The extracellular matrix protein tenascin-C is a multidomain protein that regulates cell adhesion. We used two different smooth muscle cell subtypes derived from adult and newborn rat aorta to investigate the interaction of tenascin-C or its various domains with these cells using an adhesion assay. Newborn cells were three times more adherent to tenascin-C than adult cells. Tenascin C-adhering cells remained round, whereas they spread rapidly on a fibronectin substrate. Adhesion assays showed the interaction between tenascin-C and newborn cells to be predominantly RGD-independent. Mg2+ increased newborn cell adhesion to tenascin-C in a concentration-dependent manner, whereas Ca2+ had no effect. To analyze the structure-function relationships of different domains of tenascin-C, we used recombinant full-length fibronectin-like and fibrinogen-like domains and various subdomains corresponding to the alternatively spliced regions of tenascin-C. The cells adhered to the fibrinogen-like domain but not to the fibronectin-like domain or its subdomains. As with the intact tenascin-C molecule, adherent cells remained round, and the Mg2+, but not Ca2+, promoted this interaction. The interaction of cells with the fibrinogen-like region was further mapped to a 30-amino acid peptide located near the carboxyl-terminal part of the tenascin-C molecule. The same 30-amino acid peptide was active in promoting cell migration. Our results provide a basis for understanding the mechanism of interaction of tenascin-C with smooth muscle cells and a framework for isolating membrane binding sites that mediate the cellular responses to this molecule.
LaFleur
D W
DW
Atherosclerosis Research Center, Division of Cardiology, Burns and Allen Research Institute, Cedar-Sinai Medical Center, University of California School of Medicine, Los Angeles, California 90048, USA.
Chiang
J
J
Fagin
J A
JA
Schwartz
S M
SM
Shah
P K
PK
Wallner
K
K
Forrester
J S
JS
Sharifi
B G
BG
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D002478:Cells, Cultured; D004492:Edetic Acid / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D051381:Rats; D019063:Tenascin / Q000378:metabolism*
D009842:Oligopeptides; D019063:Tenascin; C047981:arginyl-glycyl-aspartic acid; D005340:Fibrinogen; D004492:Edetic Acid; D008274:Magnesium; D002118:Calcium