Abstract |
In this study we characterized alpha v beta 5 integrin on HT-1080 fibrosarcoma cells. First, alpha v beta 5 integrin was immunoprecipitated by 125I-surface labeled HT-1080 cells using a polyclonal antibody specific for beta 5 subunit (cytoplasmic domain). A heterodimer consisting of a beta 5-chain running at 100 kD (reduced) and 90 kD (non-reduced) associated with an alpha-chain 145 kD (non-reduced) and 125 kD (reduced) was obtained by SDS-PAGE and autoradiography. By double-immunofluorescence labeling, we then investigated alpha v beta 5 distribution on HT-1080 cells. Upon staining with anti-beta 5 subunit antibody, alpha v beta 5 was detected in focal contacts on cells attached to vitronectin (vn), co-localizing with vinculin at the end of actin filaments. Comparative analysis of alpha v beta 5 and alpha v beta 3 showed that both receptors can occupy the same focal contact, although on the same cell mostly they are clustered in independent focal contacts. Focal distribution of alpha v beta 5 was also found on normal human fibroblasts attached to vn, suggesting that this is not a specific feature of HT-1080 cells. Finally, we investigated the role of alpha v beta 5 and alpha v beta 3 integrins in mediating HT-1080 cell adhesion to vn. Inhibition studies using antibodies with function-blocking activity to alpha v beta 5 and alpha v beta 3 suggest a primary role of alpha v beta 5 to support cell adhesion, with a weak contribute of alpha v beta 3. Their activity can be modulated by divalent cations. Our results provide the first evidence of focal distribution of alpha v beta 5 integrin on cells attached to vn.
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Authors | G Conforti, M Calza, A Beltrán-Nuñez |
Journal | Cell adhesion and communication
(Cell Adhes Commun)
Vol. 1
Issue 4
Pg. 279-93
(Jan 1994)
ISSN: 1061-5385 [Print] Switzerland |
PMID | 7521757
(Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Glycoproteins
- Integrins
- Receptors, Cytoadhesin
- Receptors, Vitronectin
- Vitronectin
- integrin alphaVbeta5
- Magnesium
- Calcium
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Topics |
- Binding Sites
- Calcium
(pharmacology)
- Cell Adhesion
(drug effects, physiology)
- Cell Membrane
(metabolism)
- Cells, Cultured
- Fibroblasts
(metabolism)
- Fibrosarcoma
(metabolism)
- Fluorescent Antibody Technique
- Glycoproteins
(metabolism)
- Humans
- Integrins
(immunology, isolation & purification, metabolism)
- Kinetics
- Magnesium
(pharmacology)
- Precipitin Tests
- Receptors, Cytoadhesin
(metabolism)
- Receptors, Vitronectin
- Tumor Cells, Cultured
(metabolism)
- Vitronectin
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