Integrin-associated protein immunoglobulin domain is necessary for efficient vitronectin bead binding.

Lindberg, Frederik P.; Gresham, Hattie D.; Reinhold, Martina I.; Brown, Eric J.

doi:10.1083/jcb.134.5.1313

Cited by 120 publications

(117 citation statements)

References 40 publications

Supporting

Mentioning

111

Contrasting

Unclassified

Order By: Relevance

“…With a few exceptions (4), the CD47 antibody B6H12 has been generally found to block responses mediated by other CD47 ligands (7,17,(31)(32)(33)(34)(35). Our data confirm that B6H12 reverses the activation of ␣ v ␤ 3 integrin function stimulated by a CD47-binding peptide from TSP1, but we also show that the antibody has a direct stimulating function for at least two ␤ 1 integrins in the same cells.…”

Section: A Cd47-binding Peptide Stimulatessupporting

confidence: 77%

“…Involvement of different integrins in the opposing responses to B6H12 on vitronectin and NoC2 was confirmed using a specific ␣ v integrin antagonist, which reversed FIRVVMYEGKK-enhanced spreading on vitronectin but not on NoC2 (results not shown). B6H12 was previously considered to be a function-blocking antibody for CD47 (7,17,(31)(32)(33)(34)(35), but the above results demonstrate that this CD47 antibody can both positively and negatively modulate integrin functions. Furthermore, enhancement of some TSP1 peptide responses by the antibody indicated that B6H12 does not directly inhibit binding to their cellular targets.…”

Section: A Cd47-binding Peptide Stimulatesmentioning

confidence: 83%

See 1 more Smart Citation

Regulation of Integrin Function by CD47 Ligands

Barazi

Cashel

et al. 2002

Journal of Biological Chemistry

View full text Add to dashboard Cite

CD47 (integrin-associated protein) is an integral membrane protein that is required for granulocyte and T cell recruitment to sites of infection (1, 2), and its absence on red blood cells leads to their rapid macrophage-mediated clearance (3). CD47 may also function as a costimulator to regulate T cell activation, survival, and Th1 versus Th2 differentiation (4, 5). Endogenous ligands for the extracellular domain of CD47 include the secreted protein thrombospondin-1 (TSP1) 1 and potentially other members of the thrombospondin family, several integrins (6 -9), and some members of the signal-regulatory protein family (3, 10 -13). Engagement of CD47 by soluble ligands or signal-regulatory protein counter receptors modulates several cell signaling pathways, including activation of a heterotrimeric G protein (14).Although some signal transduction through CD47 is integrin-independent (4, 15, 16), association of CD47 with certain integrins was found to modulate their function to mediate cell adhesion or motility (6,8,9,17). In addition to its known functional and physical interactions with ␣ v ␤ 3 , ␣ IIb ␤ 3 , and ␣ 2 ␤ 1 integrins, several publications have suggested an association of CD47 with ␣ 4 ␤ 1 integrin. CD47 and ␣ 4 ␤ 1 were colocalized on microvilli of K562 erythroleukemia cells (18), and CD47-dependent arrest of T cells on inflammatory endothelium could be blocked by antibodies that prevent ␣ 4 ␤ 1 integrin binding to VCAM-1 (2). In the latter study, ligation of CD47 by TSP1 or signal-regulatory protein 1␣ was inferred to activate ␣ 4 ␤ 1 integrin on T cells, although this was not demonstrated either functionally or biochemically.We recently found that CD47 expression is required for stimulation of T cell motility and expression of MMP-2 stimulated by ␣ 4 ␤ 1 integrin ligands (19). An antibody to CD47 also blocked the motility response to an ␣ 4 ␤ 1 integrin ligand (19). Therefore, at least a functional interaction occurs between CD47 and ␣ 4 ␤ 1 integrin.We identified a binding site for ␣ 4 ␤ 1 integrin in the Nterminal domains of TSP1 and TSP2 (19), whereas two binding sites for CD47 have been localized to the C-terminal domain of TSP1 (for review, see Ref. 20). Thus, TSP1 could potentially regulate its own interaction with ␣ 4 ␤ 1 integrin through simultaneous interactions with CD47 and ␣ 4 ␤ 1 integrin on a T cell, analogous to the ability of soluble TSP1 to stimulate ␣ v ␤ 3 integrin-dependent melanoma cell adhesion to immobilized TSP1 (21).To define a molecular basis for functional cross-talk between these two receptors, we have examined the effect of CD47 ligands on the function of ␣ 4 ␤ 1 integrin in T cells and melanoma cells. We confirmed that ligation of CD47 can activate ␣ 4 ␤ 1 integrin function but unexpectedly found the mechanism of this activity to be CD47 ligand-dependent. We further show that CD47 ligation differentially activates and inactivates ␣ v ␤ 3 and ␣ 4 ␤ 1 in melanoma cells and ␣ 4 ␤ 1 and ␣ 5 ␤ 1 in Jurkat cells. Unexpectedly, but consistent with a recent report demonstrating C...

show abstract

Section: A Cd47-binding Peptide Stimulatessupporting

confidence: 77%

Section: A Cd47-binding Peptide Stimulatesmentioning

confidence: 83%

Regulation of Integrin Function by CD47 Ligands

Barazi

Cashel

et al. 2002

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…The stable transfections of ␣ v ␤ 3 , CD47, and IgV-GPI have been previously reported by Lindberg et al (13), and the cells used in this study were derived from the same lines. For all experiments, OV10 cells were previously treated with serum-free media for 16 -18 h. Cell manipulations were carried out in Hanks Balanced Salt Solution containing 20 mM HEPES pH 7.5 (HBSS) with additional reagents for each application.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, 4N1K peptide-induced activation of ␣ IIb ␤ 3 , as measured by binding of PAC-1 antibody to transfected cells, required only the presence of the extracellular IgV domain of CD47, added either as a soluble protein or expressed with a generic membrane anchor (12). In addition, a previous study had shown that expression of the CD47 extracellular IgV domain in ovarian carcinoma cells was required for ␣ v ␤ 3 -mediated binding of vitronectin-coated beads (13). These data indicate that the physical association of only the IgV domain of CD47 can affect ␤ 3 integrin function.…”

mentioning

confidence: 99%

Cholesterol-independent Interactions with CD47 Enhance αvβ3 Avidity

McDonald

Zheleznyak

Frazier

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

Expression in OV10 cells of either wild-type CD47 or its extracellular IgV domain linked to a glycosylphosphatidylinositol anchor-(IgV-GPI) enhanced ligand-induced ␣ v ␤ 3 activation as detected by the binding of LIBS1 and LIBS6 mAbs. The amplitude of LIBS binding was greater with both CD47 and IgV-GPI expression, indicating an increase in the population of "activable" integrin molecules. Expression of either CD47 species also increased ␣ v ␤ 3 -mediated adhesion to vitronectin, and to surfaces coated with the anti-␤ 3 antibody AP3, because of enhanced clustering of ␣ v ␤ 3 as confirmed by chemical cross-linking. Cholesterol depletion with methyl-␤-cyclodextrin did not prevent the increase in anti-LIBS binding, but reduced cell adhesion to vitronectin and AP3. However, cells expressing CD47 were partially insulated against this disruption, and IgV-GPI was even more effective. Both CD47 and IgV-GPI were found in cholesterol-rich rafts prepared in the absence of detergent, but only CD47 could recruit ␣ v ␤ 3 and its associated signaling molecules to these domains. Thus CD47-␣ v ␤ 3 complexes in cholesterol-rich raft domains appear to engage in G i -dependent signaling whereas CD47-␣ v ␤ 3 interactions that lead to integrin clustering are also detergent resistant, but are insensitive to cholesterol depletion and do not require the transmembrane region of CD47.

show abstract

“…The wild-type and mutant SHPS-1 cDNAs were inserted separately into the EcoRI and NotI sites of the pTracerCMV vector (Invitrogen). The full-length mouse CD47 cDNA was excised from pIAP328 (32) and subcloned into pTracerCMV. The pRc/CMV vector encoding hemagglutinin (HA) 1 epitope-tagged mouse focal adhesion kinase (FAK) was provided by S. Hanks (Vanderbilt University).…”

Section: Methodsmentioning

confidence: 99%