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Published on: June 13, 2014
Ephrin-A5 modulates cell adhesion and morphology in an integrin-dependent manner
1Departments of Oncology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
The EMBO Journal
|October 18, 2000
Summary
Ephrin-A5, a signaling molecule, regulates cell adhesion and morphology crucial for neuronal guidance. It activates beta1 integrin and downstream signaling pathways, influencing cell interactions with extracellular substrates.
Area of Science:
- Cell Biology
- Neuroscience
- Molecular Biology
Background:
- Ephrins are key ligands for Eph receptor tyrosine kinases, vital in nervous and vascular system development.
- Ephrins function not only as ligands but also as signaling receptors, mediating bidirectional communication.
- Previous studies demonstrated ephrin-A5 signaling within caveola-like domains, enhancing cell adhesion to fibronectin.
Purpose of the Study:
- To investigate the role of ephrin-A5 in neuronal guidance.
- To elucidate the downstream signaling events triggered by ephrin-A5 activation.
- To understand how ephrin-A5 influences cell adhesion and morphology.
Main Methods:
- Cell-based assays to study cell adhesion and morphology changes.
- Analysis of protein tyrosine kinase activation (Src family kinases).
- Investigating the role of ERK-1 and ERK-2 activation in cellular responses.
Main Results:
- Ephrin-A5 activation initiates sequential events: initial cell adhesion changes followed by morphological alterations.
- Both adhesion and morphological changes are dependent on beta1 integrin activation.
- Src family kinases are involved in beta1 integrin activation.
- Prolonged activation of ERK-1 and ERK-2 is essential for the observed changes in cell morphology.
Conclusions:
- Ephrin-A5 plays a significant role in neuronal guidance by controlling sequential biological events.
- The findings highlight a novel function for class A ephrins in modulating cell substrate affinity via integrin regulation.
- This study reveals a new mechanism by which ephrins influence cell behavior through integrin and kinase signaling pathways.
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01:15Activation of Integrins
Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
01:17Intracellular Signaling Affects Focal Adhesions
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01:03Anchoring Junctions
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01:24Adherens Junctions
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01:22Role of Ephrin-Eph Signalling in Intestinal Stem Cell Renewal
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