Role for ?6 integrin during lens development: Evidence for signaling through IGF-1R and ERK
| Autor: | Marilyn J. Woolkalis, Liping Zhang, A. Sue Menko, Jian Zhou, Janice L. Walker |
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| Rok vydání: | 2002 |
| Předmět: |
Recombinant Fusion Proteins
Cellular differentiation Integrin Coturnix Integrin alpha6 Transfection CD49c Receptor IGF Type 1 Collagen receptor Growth factor receptor Antigens CD Lens Crystalline Animals Phosphorylation Cells Cultured Mitogen-Activated Protein Kinase 1 Mitogen-Activated Protein Kinase 3 biology Cell Differentiation Crystallins Cell biology Enzyme Activation Integrin alpha M biology.protein Integrin beta 6 Laminin Mitogen-Activated Protein Kinases Signal transduction Protein Processing Post-Translational Cell Division Signal Transduction Developmental Biology |
| Zdroj: | Developmental Dynamics. 223:273-284 |
| ISSN: | 1097-0177 1058-8388 |
| DOI: | 10.1002/dvdy.10050 |
| Popis: | We show that alpha 6 integrin function was required for normal lens cell differentiation by using an antisense construct to suppress alpha 6 integrin expression. To elucidate the mechanism by which this integrin functions in the regulation of the lens cell differentiation process, we determined the molecular composition of alpha 6 integrin signaling complexes at distinct stages of differentiation in vivo. Because both alpha 6 integrin and insulin-like growth factor-1 (IGF-1) have been implicated in signaling lens cell differentiation, we examined the possibility that they formed a signaling complex in the embryonic lens. Coprecipitation analysis revealed that alpha 6 integrin/IGF-1 receptor complexes were present and that their association was greatest in the equatorial zone, the region of the embryonic lens in which lens cells proliferate and then initiate their differentiation. These results provide in vivo support for the formation of integrin/growth factor receptor signaling complexes. We also found that extracellular signal-regulated kinase (ERK), a downstream effector of both integrin and growth factor receptor signaling pathways, was associated with the alpha 6 integrin signaling complexes in the embryonic lens. This result was supported by our findings that activated ERK, in addition to its nuclear location, localized to lens cell membranes in specific regions of cell-matrix and cell-cell contact. A connection between integrin ligand engagement and ERK activation was shown in vitro after lens cell attachment to laminin. These results demonstrate that alpha 6 integrin function is required for the early stages of lens cell differentiation most likely through its association with the IGF-1 receptor and the activation of ERK. |
| Databáze: | OpenAIRE |
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