Altered localization and cytoplasmic domain-binding properties of tyrosine-phosphorylated beta 1 integrin
| Autor: | E Larsson, M W Johansson, Erkki Ruoslahti, B Lüning, E B Pasquale |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Integrins
Integrin Molecular Sequence Data Peptide SH2 domain Mice Cell Adhesion Animals Amino Acid Sequence Tyrosine Phosphotyrosine Peptide sequence Interleukin 12 receptor beta 1 subunit chemistry.chemical_classification biology Integrin beta1 Cell Membrane Cell Biology 3T3 Cells Articles Cell Transformation Viral Molecular biology Cell Compartmentation chemistry Avian Sarcoma Viruses biology.protein Phosphorylation Integrin beta 6 Peptides |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 0021-9525 |
| Popis: | We describe a novel approach to study tyrosine-phosphorylated (PY) integrins in cells transformed by virally encoded tyrosine kinases. We have synthesized a peptide (PY beta 1 peptide) that represents a portion of the cytoplasmic domain of the beta 1 integrin subunit and is phosphorylated on the tyrosine residue known to be the target of oncogenic tyrosine kinases. Antibodies prepared against the PY beta 1 peptide, after removal of cross-reacting antibodies by absorption and affinity purification, recognized the PY beta 1 peptide and the tyrosine-phosphorylated form of the intact beta 1 subunit, but did not bind the nonphosphorylated beta 1 peptide, the nonphosphorylated beta 1 subunit or other unrelated tyrosine-phosphorylated proteins. The anti-PY beta 1 antibodies labeled the podosomes of Rous sarcoma virus-transformed fibroblasts, but did not detectably stain nontransformed fibroblasts. The localization of the tyrosine phosphorylated beta 1 subunits appeared distinct from that of the beta 1 subunit. Adhesion plaques were stained by the anti-beta 1 subunit antibodies in Rous sarcoma virus-transformed fibroblasts plated on fibronectin, whereas neither podosomes nor adhesion plaques were labeled on vitronectin or on uncoated plates. Anti-phosphotyrosine antibodies labeled podosomes, adhesion plaques and cell-cell boundaries regardless of the substratum. One of the SH2 domains of the p85 subunit of phosphatidylinositol-3-kinase bound to the PY beta 1 peptide, but not to the non-phosphorylated beta 1 cytoplasmic peptide. Other SH2 domains did not bind to the PY beta 1 peptide. These results show that the phosphorylated form of the beta 1 integrin subunit is detected in a different subcellular localization than the nonphosphorylated form and suggest that the phosphorylation on tyrosine of the beta 1 subunit cytoplasmic domain may affect cellular signaling pathways. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|