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The α 4 β 1 integrin can mediate leukocyte adhesion to casein and denatured protein substrates
Author(s) -
Davis George E.,
Thomas J. Scott,
Madden Steven
Publication year - 1997
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.62.3.318
Subject(s) - biology , integrin , adhesion , casein , cell adhesion , microbiology and biotechnology , immunology , biochemistry , receptor , cell , chemistry , organic chemistry
An understanding of the binding specificity of leukocyte integrins is important to determine the range of ligands that interact with these receptors during inflammatory processes. In this study we show that the α 4 β 1 integrin can interact with casein and denatured albumin and promote leukocyte adhesion through these interactions. This was demonstrated with the use of blocking antibodies directed to α 4 β 1 and peptide adhesion competitors containing the α 4 β 1 binding tripeptide, Leu‐Asp‐Val (LDV). Consistent with this data, the adhesion is completely divalent cation‐dependent and is stimulated by known activators of leukocyte integrin function, namely phorbol ester and the β 1 integrin activating antibody, 8A2. It is interesting to note that neither bovine α‐casein or human albumin contain an LDV site (present in the CS‐1 site of alternatively spliced fibronectin) or an IDS site (present in VCAM‐1) yet they promote adhesion through this integrin. Furthermore, α 4 β 1 directly binds to Sepharose columns containing casein, casein fragments, or denatured albumin but does not bind columns containing native albumin. These data suggest that the binding specificity for the α 4 β 1 integrin is considerably broader than previously realized. This work has implications for how subsets of leukocytes may interact with damaged proteins during tissue injury and inflammation. J. Leukoc. Biol. 62: 318–328; 1997.