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The thrombospondin receptor CD47 (IAP) modulates and associates with alpha2 beta1 integrin in vascular smooth muscle cells.

ABSTRACT: The carboxyl-terminal domain of thrombospondin-1 enhances the migration and proliferation of smooth muscle cells. Integrin-associated protein (IAP or CD47) is a receptor for the thrombospondin-1 carboxyl-terminal cell-binding domain and binds the agonist peptide 4N1K (kRFYVVMWKk) from this domain. 4N1K peptide stimulates chemotaxis of both human and rat aortic smooth muscle cells on gelatin-coated filters. The migration on gelatin is specifically blocked by monoclonal antibodies against IAP and a beta1 integrin, rather than alphav beta3 as found previously for 4N1K-stimulated chemotaxis of endothelial cells on gelatin. Both human and rat smooth muscle cells displayed a weak migratory response to soluble type I collagen; however, the presence of 4N1K peptide or intact thrombospondin-1 provoked a synergistic chemotactic response that was partially blocked by antibodies to alpha2 and beta1 integrin subunits and to IAP. A combination of antialpha2 and IAP monoclonal antibodies completely blocked chemotaxis. RGD peptide and antialphav beta3 mAb were without effect. 4N1K and thrombospondin-1 did not augment the chemotactic response of smooth muscle cells to fibronectin, vitronectin, or collagenase-digested type I collagen. Complex formation between alpha2 beta1 and IAP was detected by the coimmunoprecipitation of both alpha2 and beta1 integrin subunits with IAP. These data suggest that IAP can associate with alpha2 beta1 integrin and modulate its function.

SUBMITTER: Wang XQ

PROVIDER: S-EPMC25313 | biostudies-literature | 1998 Apr

REPOSITORIES: biostudies-literature

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The thrombospondin receptor CD47 (IAP) modulates and associates with alpha2 beta1 integrin in vascular smooth muscle cells.

Wang X Q XQ Frazier W A WA

Molecular biology of the cell 19980401 4

The carboxyl-terminal domain of thrombospondin-1 enhances the migration and proliferation of smooth muscle cells. Integrin-associated protein (IAP or CD47) is a receptor for the thrombospondin-1 carboxyl-terminal cell-binding domain and binds the agonist peptide 4N1K (kRFYVVMWKk) from this domain. 4N1K peptide stimulates chemotaxis of both human and rat aortic smooth muscle cells on gelatin-coated filters. The migration on gelatin is specifically blocked by monoclonal antibodies against IAP and ...[more]

PMID: 9529384

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Project description:Previous reports demonstrate that the Î±2-integrin (Î±2) mediates pancreatic ductal adenocarcinoma (PDAC) cell interaction with collagens. We found that untransformed pancreatic ductal epithelial cells and well-differentiated PDAC cells use Î±2 exclusively to adhere and migrate on collagenI. In contrast, poorly-differentiated PT45P1 and MIAPaCa2 cells demonstrate reduced reliance on, or complete loss of Î±2, respectively. Further, well-differentiated PDAC lines exhibit reduced in vitro invasion compared to poorly-differentiated lines, and Î±2-blockade suppressed invasion of well-differentiated lines exclusively. Based on these data and the demonstrated role of Î±2 in maintaining tissue architecture in other organs, we hypothesized that Î±2 may actually suppress the malignant phenotype in PDAC. Accordingly, stable ectopic expression of Î±2 in MIAPaCa2 cells (MP2-Î±2) retarded in vitro invasion. MP2-Î±2 cells maintained on collagenI were more invasion-retarded than MP2-Î±2 cells maintained in standard tissue culture, and demonstrated higher Î±2Î²1 expression that was reflected in faster and more complete adhesion/migration on collagenI. Affymetrix gene expression profiling of Î±2-expressing and mock-transfected cells revealed that kallikrein-related peptidases (KLK)-5, 6 and 7 were specifically upregulated by Î±2. Accordingly, well-differentiated PDAC lines express KLK-5, 6 and 7 and KLK blockade increased invasion as well as collagenI-migration in KLK-positive lines. Importantly, an Î±2 cytoplasmic deletion mutant promoted KLK expression and retarded invasion, while an Î±9Î±2 chimera retarded invasion less efficiently, and did not impact KLK expression. These data demonstrate for the first time that the Î±2-ectodomain and KLKâ??s coordinately regulate a less invasive phenotype in PDAC cells. Experiment Overall Design: Affymetrix global gene arrays were used to analyse differences in gene expression patterns in MIAPaCa2 cells stably reexpressing the alpha2 integrin, a cytoplasmic deletion of the alpha2 integrin (dCYTO) or an alpha9 ectodomain and transmembrane domain/alpha2 cytoplasmic domain chimera, versus vector-only mock controls. RNA was harvested from cells passaged identically and maitained under standard tissue culture conditions or on collagenI- or tenascin FNIII-coated plates.. Experiment Overall Design: Genetic manipulation (stable transgene expression)

Dataset Information

The thrombospondin receptor CD47 (IAP) modulates and associates with alpha2 beta1 integrin in vascular smooth muscle cells.

Publications

The thrombospondin receptor CD47 (IAP) modulates and associates with alpha2 beta1 integrin in vascular smooth muscle cells.

Similar Datasets

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