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Cranial neural crest recycle surface integrins in a substratum-dependent manner to promote rapid motility.

Strachan LR, Condic ML - J. Cell Biol. (2004)

Bottom Line: NCCs showed both ligand- and receptor-specific integrin regulation in vitro.On laminin, NCCs accumulated internalized laminin but not fibronectin receptors over 20 min, whereas on fibronectin neither type of receptor accumulated internally beyond 2 min.Internalized laminin receptors colocalized with receptor recycling vesicles and were subsequently recycled back to the cell surface.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.

ABSTRACT
Cell migration is essential for proper development of numerous structures derived from embryonic neural crest cells (NCCs). Although the migratory pathways of NCCs have been determined, the molecular mechanisms regulating NCC motility remain unclear. NCC migration is integrin dependent, and recent work has shown that surface expression levels of particular integrin alpha subunits are important determinants of NCC motility in vitro. Here, we provide evidence that rapid cranial NCC motility on laminin requires integrin recycling. NCCs showed both ligand- and receptor-specific integrin regulation in vitro. On laminin, NCCs accumulated internalized laminin but not fibronectin receptors over 20 min, whereas on fibronectin neither type of receptor accumulated internally beyond 2 min. Internalized laminin receptors colocalized with receptor recycling vesicles and were subsequently recycled back to the cell surface. Blocking receptor recycling with bafilomycin A inhibited NCC motility on laminin, indicating that substratum-dependent integrin recycling is essential for rapid cranial neural crest migration.

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Summary of cranial NCC migration on laminin. On low concentrations of laminin there is high receptor expression at the surface, cell velocities are slower, and motility does not depend on receptor recycling. On high concentrations of laminin there is low receptor expression at the surface, cell velocities are higher, and rapid motility depends on recycling of receptors from internal pools.
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fig6: Summary of cranial NCC migration on laminin. On low concentrations of laminin there is high receptor expression at the surface, cell velocities are slower, and motility does not depend on receptor recycling. On high concentrations of laminin there is low receptor expression at the surface, cell velocities are higher, and rapid motility depends on recycling of receptors from internal pools.

Mentions: These factors suggest a model for NCC migration on laminin (Fig. 6). Our model proposes that efficient motility on laminin is largely regulated by the appropriate matching of cell surface adhesion receptor number to ligand availability. On low concentrations of laminin, there is very little ligand available (calculations from our current measurements of radiolabeled laminin binding indicate that on low laminin only ∼300 molecules of laminin are bound per μm2) so efficient motility requires a large number of receptors on the cell surface to increase the probability of ligand binding events. In contrast, on high concentrations of laminin (10-fold higher density), ligand is more readily available and fewer receptors are needed on the surface to achieve the same probability of ligand binding. In fact, on high substratum concentrations, high surface receptor number would increase adhesion and concomitantly decrease motility. Thus, on high ligand concentrations, motile NCCs rely on recycling of internal receptor pools to promote ligand binding events at the leading edge of the cell, whereas on low ligand concentrations the receptors are already at the cell surface.


Cranial neural crest recycle surface integrins in a substratum-dependent manner to promote rapid motility.

Strachan LR, Condic ML - J. Cell Biol. (2004)

Summary of cranial NCC migration on laminin. On low concentrations of laminin there is high receptor expression at the surface, cell velocities are slower, and motility does not depend on receptor recycling. On high concentrations of laminin there is low receptor expression at the surface, cell velocities are higher, and rapid motility depends on recycling of receptors from internal pools.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172496&req=5

fig6: Summary of cranial NCC migration on laminin. On low concentrations of laminin there is high receptor expression at the surface, cell velocities are slower, and motility does not depend on receptor recycling. On high concentrations of laminin there is low receptor expression at the surface, cell velocities are higher, and rapid motility depends on recycling of receptors from internal pools.
Mentions: These factors suggest a model for NCC migration on laminin (Fig. 6). Our model proposes that efficient motility on laminin is largely regulated by the appropriate matching of cell surface adhesion receptor number to ligand availability. On low concentrations of laminin, there is very little ligand available (calculations from our current measurements of radiolabeled laminin binding indicate that on low laminin only ∼300 molecules of laminin are bound per μm2) so efficient motility requires a large number of receptors on the cell surface to increase the probability of ligand binding events. In contrast, on high concentrations of laminin (10-fold higher density), ligand is more readily available and fewer receptors are needed on the surface to achieve the same probability of ligand binding. In fact, on high substratum concentrations, high surface receptor number would increase adhesion and concomitantly decrease motility. Thus, on high ligand concentrations, motile NCCs rely on recycling of internal receptor pools to promote ligand binding events at the leading edge of the cell, whereas on low ligand concentrations the receptors are already at the cell surface.

Bottom Line: NCCs showed both ligand- and receptor-specific integrin regulation in vitro.On laminin, NCCs accumulated internalized laminin but not fibronectin receptors over 20 min, whereas on fibronectin neither type of receptor accumulated internally beyond 2 min.Internalized laminin receptors colocalized with receptor recycling vesicles and were subsequently recycled back to the cell surface.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.

ABSTRACT
Cell migration is essential for proper development of numerous structures derived from embryonic neural crest cells (NCCs). Although the migratory pathways of NCCs have been determined, the molecular mechanisms regulating NCC motility remain unclear. NCC migration is integrin dependent, and recent work has shown that surface expression levels of particular integrin alpha subunits are important determinants of NCC motility in vitro. Here, we provide evidence that rapid cranial NCC motility on laminin requires integrin recycling. NCCs showed both ligand- and receptor-specific integrin regulation in vitro. On laminin, NCCs accumulated internalized laminin but not fibronectin receptors over 20 min, whereas on fibronectin neither type of receptor accumulated internally beyond 2 min. Internalized laminin receptors colocalized with receptor recycling vesicles and were subsequently recycled back to the cell surface. Blocking receptor recycling with bafilomycin A inhibited NCC motility on laminin, indicating that substratum-dependent integrin recycling is essential for rapid cranial neural crest migration.

Show MeSH
Related in: MedlinePlus