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The syndecan-1 ectodomain regulates alphavbeta3 integrin activity in human mammary carcinoma cells.

Beauvais DM, Burbach BJ, Rapraeger AC - J. Cell Biol. (2004)

Bottom Line: This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled.Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration.Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.

ABSTRACT
The alpha(v)beta(3) integrin participates in cell morphogenesis, growth factor signaling, and cell survival. Activation of the integrin is central to these processes and is influenced by specific ECM components, which engage both integrins and syndecans. This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled. The integrin is dependent on the syndecan to become activated and to mediate signals required for MDA-MB-231 and MDA-MB-435 human mammary carcinoma cell spreading on vitronectin or S1-specific antibody. Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration. Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

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Related in: MedlinePlus

Deletion of a region of the S1ED blocks αvβ3-mediated cell spreading. (A) Graphic representation of S1 expression constructs transfected into MDA-MB-231 cells and their relative expression levels as detected by FACS (mean fluorescent intensity). Asterisks indicate the HS attachment sites. (B) Cells transfected with empty vector (NEO) or S1 constructs were seeded in plating medium on wells coated with either anti-hS1 mAb B-B4 (NEO + inset, hS1, and insets of mS1) or anti-mS1 mAb 281.2 (all others). Where noted, cells were pretreated in suspension with 1 μg/ml mAb P5D2 for 15 min before plating. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.
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fig6: Deletion of a region of the S1ED blocks αvβ3-mediated cell spreading. (A) Graphic representation of S1 expression constructs transfected into MDA-MB-231 cells and their relative expression levels as detected by FACS (mean fluorescent intensity). Asterisks indicate the HS attachment sites. (B) Cells transfected with empty vector (NEO) or S1 constructs were seeded in plating medium on wells coated with either anti-hS1 mAb B-B4 (NEO + inset, hS1, and insets of mS1) or anti-mS1 mAb 281.2 (all others). Where noted, cells were pretreated in suspension with 1 μg/ml mAb P5D2 for 15 min before plating. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.

Mentions: To confirm that the S1ED is necessary and sufficient for the activation of αvβ3 integrin–dependent cell spreading, MDA-MB-231 cells were transfected with mS1 expression constructs (Fig. 6 A). Populations of high-expressing clones were sorted by FACS analysis using mAb 281.2, an antibody that selectively recognizes mS1, to ensure comparable levels of expression. Cells were then plated on S1-specific antibodies to assess their ability to spread in response to S1 ligation.


The syndecan-1 ectodomain regulates alphavbeta3 integrin activity in human mammary carcinoma cells.

Beauvais DM, Burbach BJ, Rapraeger AC - J. Cell Biol. (2004)

Deletion of a region of the S1ED blocks αvβ3-mediated cell spreading. (A) Graphic representation of S1 expression constructs transfected into MDA-MB-231 cells and their relative expression levels as detected by FACS (mean fluorescent intensity). Asterisks indicate the HS attachment sites. (B) Cells transfected with empty vector (NEO) or S1 constructs were seeded in plating medium on wells coated with either anti-hS1 mAb B-B4 (NEO + inset, hS1, and insets of mS1) or anti-mS1 mAb 281.2 (all others). Where noted, cells were pretreated in suspension with 1 μg/ml mAb P5D2 for 15 min before plating. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172512&req=5

fig6: Deletion of a region of the S1ED blocks αvβ3-mediated cell spreading. (A) Graphic representation of S1 expression constructs transfected into MDA-MB-231 cells and their relative expression levels as detected by FACS (mean fluorescent intensity). Asterisks indicate the HS attachment sites. (B) Cells transfected with empty vector (NEO) or S1 constructs were seeded in plating medium on wells coated with either anti-hS1 mAb B-B4 (NEO + inset, hS1, and insets of mS1) or anti-mS1 mAb 281.2 (all others). Where noted, cells were pretreated in suspension with 1 μg/ml mAb P5D2 for 15 min before plating. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.
Mentions: To confirm that the S1ED is necessary and sufficient for the activation of αvβ3 integrin–dependent cell spreading, MDA-MB-231 cells were transfected with mS1 expression constructs (Fig. 6 A). Populations of high-expressing clones were sorted by FACS analysis using mAb 281.2, an antibody that selectively recognizes mS1, to ensure comparable levels of expression. Cells were then plated on S1-specific antibodies to assess their ability to spread in response to S1 ligation.

Bottom Line: This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled.Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration.Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.

ABSTRACT
The alpha(v)beta(3) integrin participates in cell morphogenesis, growth factor signaling, and cell survival. Activation of the integrin is central to these processes and is influenced by specific ECM components, which engage both integrins and syndecans. This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled. The integrin is dependent on the syndecan to become activated and to mediate signals required for MDA-MB-231 and MDA-MB-435 human mammary carcinoma cell spreading on vitronectin or S1-specific antibody. Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration. Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

Show MeSH
Related in: MedlinePlus