journal article

Journal Article

Text

Journal of Biological Chemistry. 2008, 283(42), p. 28149-28157

Laminin Isoforms Containing the γ3 Chain Are Unable to Bind to Integrins due to the Absence of the Glutamic Acid Residue Conserved in the C-terminal Regions of the γ1 and γ2 Chains

Nishiuchi, Ryoko

American Society for Biochemistry and Molecular Biology

English

Text

2008-10

https://doi.org/10.1074/jbc.M803553200

This research was originally published in the Journal of Biological Chemistry. Hiroyuki Ido, Shunsuke Ito, Yukimasa Taniguchi, Maria Hayashi, Ryoko Sato-Nishiuchi, Noriko Sanzen, Yoshitaka Hayashi, Sugiko Futaki and Kiyotoshi Sekiguchi. Laminin Isoforms Containing the γ3 Chain Are Unable to Bind to Integrins due to the Absence of the Glutamic Acid Residue Conserved in the C-terminal Regions of the γ1 and γ2 Chains. J. Biol. Chem. 2008; 283: 28149–28157 © the American Society for Biochemistry and Molecular Biology

Laminins are the major cell adhesive proteins in basement membranes, and consist of three subunits termed α, β, and γ. Recently, we found that the Glu residue at the third position from the C termini of the γ1 and γ2 chains is critically involved in integrin binding by laminins. However, the γ3 chain lacks this Glu residue, suggesting that laminin isoforms containing the γ3 chain may be unable to bind to integrins. To address this possibility, we expressed the E8 fragment of laminin-213 and found that it was incapable of binding to integrins. Similarly, the E8 fragment of laminin-113 was expressed and also found to be inactive in binding to integrins, confirming the distinction between the integrin binding activities of γ3 chain-containing isoforms and those containing the γ1 or γ2 chain. To further address the importance of the Glu residue, we swapped the C-terminal four amino acids of the γ3 chain with the C-terminal nine amino acids of the γ1 chain, which contain the Glu residue. The resulting chimeric E8 fragment of laminin-213 became fully active in integrin binding, whereas replacement with the nine amino acids of the γ1 chain after substitution of Gln for the conserved Glu residue failed to restore the integrin binding activity. These results provide both loss-of-function and gain-of-function evidence that laminin isoforms containing the γ3 chain are unable to bind to integrins due to the absence of the conserved Glu residue, which should play a critical role in integrin binding by laminins.

71426

Laminin Isoforms Containing the γ3 Chain Are Unable to Bind to Integrins due to the Absence of the Glutamic Acid Residue Conserved in the C-terminal Regions of the γ1 and γ2 Chains

American Society for Biochemistry and Molecular Biology

English

2008-10

Journal of Biological Chemistry

283

42

28149

28157

https://doi.org/10.1074/jbc.M803553200

https://hdl.handle.net/11094/71426