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alphavbeta5 integrin sustains growth of human pre-B cells through an RGD-independent interaction with a basic domain of the CD23 protein.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2007 Sep 14; Vol. 282 (37), pp. 27315-27326. Date of Electronic Publication: 2007 May 31. - Publication Year :
- 2007
-
Abstract
- CD23 is a type II transmembrane glycoprotein synthesized by hematopoietic cells that has biological activity in both membrane-bound and freely soluble forms, acting via a number of receptors, including integrins. We demonstrate here that soluble CD23 (sCD23) sustains growth of human B cell precursors via an RGD-independent interaction with the alphavbeta5 integrin. The integrin recognizes a tripeptide motif in a small disulfide-bonded loop at the N terminus of the lectin head region of CD23, centered around Arg(172), Lys(173), and Cys(174) (RKC). This RKC motif is present in all forms of sCD23 with cytokine-like activity, and cytokine activity is independent of the lectin head, an "inverse RGD" motif, and the CD21 and IgE binding sites. RKC-containing peptides derived from this region of CD23 bind alphavbeta5 and are biologically active. The binding and activity of these peptides is unaffected by inclusion of a short peptide containing the classic RGD sequence recognized by integrins, and, in far-Western analyses, RKC-containing peptides bind to the beta subunit of the alphavbeta5 integrin. The interaction between alphavbeta5 and sCD23 indicates that integrins deliver to cells important signals initiated by soluble ligands without the requirement for interactions with RGD motifs in their common ligands. This mode of integrin signaling may not be restricted to alphavbeta5.
- Subjects :
- Amino Acid Motifs
Amino Acid Sequence
Binding Sites
Cells, Cultured
Humans
Immunoglobulin E metabolism
Molecular Sequence Data
Protein Structure, Tertiary
Receptors, Complement 3d metabolism
Receptors, IgE metabolism
B-Lymphocytes physiology
Hematopoietic Stem Cells physiology
Integrins physiology
Oligopeptides physiology
Receptors, IgE chemistry
Receptors, Vitronectin physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 282
- Issue :
- 37
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 17540777
- Full Text :
- https://doi.org/10.1074/jbc.M609335200