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Angiomotin: an angiostatin binding protein that regulates endothelial cell migration and tube formation.

Troyanovsky B, Levchenko T, Månsson G, Matvijenko O, Holmgren L - J. Cell Biol. (2001)

Bottom Line: Transfected angiomotin as well as endogenous angiomotin protein were localized to the leading edge of migrating endothelial cells.Expression of angiomotin in endothelial cells resulted in increased cell migration, suggesting a stimulatory role of angiomotin in cell motility.These findings indicate that angiostatin inhibits cell migration by interfering with angiomotin activity in endothelial cells.

View Article: PubMed Central - PubMed

Affiliation: Center for Genomics Research and Microbiology and Tumor Biology Center, Karolinska Institutet, S-171 76 Stockholm, Sweden.

ABSTRACT
Angiostatin, a circulating inhibitor of angiogenesis, was identified by its ability to maintain dormancy of established metastases in vivo. In vitro, angiostatin inhibits endothelial cell migration, proliferation, and tube formation, and induces apoptosis in a cell type-specific manner. We have used a construct encoding the kringle domains 1--4 of angiostatin to screen a placenta yeast two-hybrid cDNA library for angiostatin-binding peptides. Here we report the identification of angiomotin, a novel protein that mediates angiostatin inhibition of migration and tube formation of endothelial cells. In vivo, angiomotin is expressed in the endothelial cells of capillaries as well as larger vessels of the human placenta. Upon expression of angiomotin in HeLa cells, angiomotin bound and internalized fluorescein-labeled angiostatin. Transfected angiomotin as well as endogenous angiomotin protein were localized to the leading edge of migrating endothelial cells. Expression of angiomotin in endothelial cells resulted in increased cell migration, suggesting a stimulatory role of angiomotin in cell motility. However, treatment with angiostatin inhibited migration and tube formation in angiomotin-expressing cells but not in control cells. These findings indicate that angiostatin inhibits cell migration by interfering with angiomotin activity in endothelial cells.

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(A) The amino acid sequence of angiomotin. The amino acid sequence of the clone derived from the yeast two-hybrid screening is underlined. (B) Genomic organization of the angiomotin gene, size of cDNA, and the open reading frame (ORF). The Genbank accession number for the angiomotin cDNA genomic sequence data are available from GenBank/EMBL/DDBJ under accession nos. AF286598 and NT_011819.
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Figure 2: (A) The amino acid sequence of angiomotin. The amino acid sequence of the clone derived from the yeast two-hybrid screening is underlined. (B) Genomic organization of the angiomotin gene, size of cDNA, and the open reading frame (ORF). The Genbank accession number for the angiomotin cDNA genomic sequence data are available from GenBank/EMBL/DDBJ under accession nos. AF286598 and NT_011819.

Mentions: We cloned and sequenced the whole gene by screening a placenta cDNA phage library with the yeast-derived sequence as a probe in combination with the 5′RACE PCR technique as described in Materials and Methods. The angiomotin cDNA genomic sequence data are available from Genbank/EMBL/DDBJ under accession nos. AF286598 and NT_011819. The cDNA contained a 2,025-bp open reading frame predicted to encode a 675 amino acid protein of an estimated molecular mass of 72 kD (Fig. 2A and Fig. B). Due to its expression in endothelial cells and its effect on cell motility, we named this protein angiomotin. The amino acid sequence did not appear to contain any signal sequence that is usually found in membrane receptors or secreted proteins. This is comparable with other plasminogen- or angiostatin-binding proteins such as alpha enolase, annexin II, or the more recently identified angiostatin-binding protein, ATP synthase (Miles et al. 1991; Das et al. 1994; Hajjar et al. 1996; Moser et al. 1999). All these proteins lack a signal peptide but still bind plasminogen or angiostatin on the endothelial cell surface.


Angiomotin: an angiostatin binding protein that regulates endothelial cell migration and tube formation.

Troyanovsky B, Levchenko T, Månsson G, Matvijenko O, Holmgren L - J. Cell Biol. (2001)

(A) The amino acid sequence of angiomotin. The amino acid sequence of the clone derived from the yeast two-hybrid screening is underlined. (B) Genomic organization of the angiomotin gene, size of cDNA, and the open reading frame (ORF). The Genbank accession number for the angiomotin cDNA genomic sequence data are available from GenBank/EMBL/DDBJ under accession nos. AF286598 and NT_011819.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199208&req=5

Figure 2: (A) The amino acid sequence of angiomotin. The amino acid sequence of the clone derived from the yeast two-hybrid screening is underlined. (B) Genomic organization of the angiomotin gene, size of cDNA, and the open reading frame (ORF). The Genbank accession number for the angiomotin cDNA genomic sequence data are available from GenBank/EMBL/DDBJ under accession nos. AF286598 and NT_011819.
Mentions: We cloned and sequenced the whole gene by screening a placenta cDNA phage library with the yeast-derived sequence as a probe in combination with the 5′RACE PCR technique as described in Materials and Methods. The angiomotin cDNA genomic sequence data are available from Genbank/EMBL/DDBJ under accession nos. AF286598 and NT_011819. The cDNA contained a 2,025-bp open reading frame predicted to encode a 675 amino acid protein of an estimated molecular mass of 72 kD (Fig. 2A and Fig. B). Due to its expression in endothelial cells and its effect on cell motility, we named this protein angiomotin. The amino acid sequence did not appear to contain any signal sequence that is usually found in membrane receptors or secreted proteins. This is comparable with other plasminogen- or angiostatin-binding proteins such as alpha enolase, annexin II, or the more recently identified angiostatin-binding protein, ATP synthase (Miles et al. 1991; Das et al. 1994; Hajjar et al. 1996; Moser et al. 1999). All these proteins lack a signal peptide but still bind plasminogen or angiostatin on the endothelial cell surface.

Bottom Line: Transfected angiomotin as well as endogenous angiomotin protein were localized to the leading edge of migrating endothelial cells.Expression of angiomotin in endothelial cells resulted in increased cell migration, suggesting a stimulatory role of angiomotin in cell motility.These findings indicate that angiostatin inhibits cell migration by interfering with angiomotin activity in endothelial cells.

View Article: PubMed Central - PubMed

Affiliation: Center for Genomics Research and Microbiology and Tumor Biology Center, Karolinska Institutet, S-171 76 Stockholm, Sweden.

ABSTRACT
Angiostatin, a circulating inhibitor of angiogenesis, was identified by its ability to maintain dormancy of established metastases in vivo. In vitro, angiostatin inhibits endothelial cell migration, proliferation, and tube formation, and induces apoptosis in a cell type-specific manner. We have used a construct encoding the kringle domains 1--4 of angiostatin to screen a placenta yeast two-hybrid cDNA library for angiostatin-binding peptides. Here we report the identification of angiomotin, a novel protein that mediates angiostatin inhibition of migration and tube formation of endothelial cells. In vivo, angiomotin is expressed in the endothelial cells of capillaries as well as larger vessels of the human placenta. Upon expression of angiomotin in HeLa cells, angiomotin bound and internalized fluorescein-labeled angiostatin. Transfected angiomotin as well as endogenous angiomotin protein were localized to the leading edge of migrating endothelial cells. Expression of angiomotin in endothelial cells resulted in increased cell migration, suggesting a stimulatory role of angiomotin in cell motility. However, treatment with angiostatin inhibited migration and tube formation in angiomotin-expressing cells but not in control cells. These findings indicate that angiostatin inhibits cell migration by interfering with angiomotin activity in endothelial cells.

Show MeSH
Related in: MedlinePlus