Identification of motifs in the fasciclin domains of the transforming growth factor-beta-induced matrix protein betaig-h3 that interact with the alphavbeta5 integrin.
betaig-h3 is a TGF-beta-induced matrix protein known to mediate the adhesion of several cell types. In this study, we found that all four of the fas-1 domains in betaig-h3 mediate MRC-5 fibroblast adhesion and that this was specifically inhibited by a function-blocking monoclonal antibody specific for the alphavbeta5 integrin. Using deletion mutants of the fourth fas-1 domain revealed the MRC-5 cell adhesion motif (denoted the YH motif) is located in amino acids 548-614. Experiments with substitution mutants showed that tyrosine 571, histidine 572, and their flanking leucine and isoleucine amino acids, which are all highly conserved in many fas-1 domains, are essential for mediating MRC-5 cell adhesion. A synthetic 18-amino acid peptide encompassing these conserved amino acids could effectively block MRC-5 cell adhesion to betaig-h3. Using HEK293 cells stably transfected with the beta5 integrin cDNA, we confirmed that the alphavbeta5 integrin is a functional receptor for the YH motif. In conclusion, we have identified a new alphavbeta5 integrin-interacting motif that is highly conserved in the fas-1 domains of many proteins. This suggests that fas-1 domain-containing proteins may perform their biological functions by interacting with integrins.
Kim
Jung-Eun
JE
Cell and Matrix Biology National Research Laboratory, Department of Biochemistry, Kyungpook National University School of Medicine, Taegu 700-422, Korea.
Jeong
Ha-Won
HW
Nam
Ju-Ock
JO
Lee
Byung-Heon
BH
Choi
Je-Yong
JY
Park
Rang-Woon
RW
Park
Jae Yong
JY
Kim
In-San
IS
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002478:Cells, Cultured; D004546:Elapid Venoms / Q000737:chemistry / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D005434:Flow Cytometry; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism*; D011485:Protein Binding; D019030:Receptors, Vitronectin / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D016212:Transforming Growth Factor beta; D000099222:betaIG-H3 Protein
D004546:Elapid Venoms; D016326:Extracellular Matrix Proteins; D016023:Integrins; D009363:Neoplasm Proteins; D019030:Receptors, Vitronectin; D016212:Transforming Growth Factor beta; D000099222:betaIG-H3 Protein; C064660:integrin alphaVbeta5; C044937:fasciculin