Limits...
Keratocytes pull with similar forces on their dorsal and ventral surfaces.

Galbraith CG, Sheetz MP - J. Cell Biol. (1999)

Bottom Line: Borisy. 1997.Cell Biol. 139:397-415).Similar forces were generated on both the ventral (0.2 nN/microm(2)) and the dorsal (0.4 nN/microm(2)) surfaces of the lamella, suggesting that dorsal matrix contacts are as effectively linked to the force-generating cytoskeleton as ventral contacts.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.

ABSTRACT
As cells move forward, they pull rearward against extracellular matrices (ECMs), exerting traction forces. However, no rearward forces have been seen in the fish keratocyte. To address this discrepancy, we have measured the propulsive forces generated by the keratocyte lamella on both the ventral and the dorsal surfaces. On the ventral surface, a micromachined device revealed that traction forces were small and rearward directed under the lamella, changed direction in front of the nucleus, and became larger under the cell body. On the dorsal surface of the lamella, an optical gradient trap measured rearward forces generated against fibronectin-coated beads. The retrograde force exerted by the cell on the bead increased in the thickened region of the lamella where myosin condensation has been observed (Svitkina, T.M., A.B. Verkhovsky, K.M. McQuade, and G. G. Borisy. 1997. J. Cell Biol. 139:397-415). Similar forces were generated on both the ventral (0.2 nN/microm(2)) and the dorsal (0.4 nN/microm(2)) surfaces of the lamella, suggesting that dorsal matrix contacts are as effectively linked to the force-generating cytoskeleton as ventral contacts. The correlation between the level of traction force and the density of myosin suggests a model for keratocyte movement in which myosin condensation in the perinuclear region generates rearward forces in the lamella and forward forces in the cell rear.

Show MeSH

Related in: MedlinePlus

Keratocytes generate large traction forces orthogonal to the direction of migration. Keratocytes generate forces perpendicular to the direction of migration as indicated by wrinkles that are parallel to the direction of motion. Deformable substratum were made by cross-linking Dow Corning 710 fluid. The stiffness of the substrata was decreased by exposure to 254 nm UV light (Burton and Taylor 1997). Keratocytes generate wrinkles that are parallel to the direction of motion, indicating that the largest traction forces are perpendicular to the direction of motion. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2168090&req=5

Figure 1: Keratocytes generate large traction forces orthogonal to the direction of migration. Keratocytes generate forces perpendicular to the direction of migration as indicated by wrinkles that are parallel to the direction of motion. Deformable substratum were made by cross-linking Dow Corning 710 fluid. The stiffness of the substrata was decreased by exposure to 254 nm UV light (Burton and Taylor 1997). Keratocytes generate wrinkles that are parallel to the direction of motion, indicating that the largest traction forces are perpendicular to the direction of motion. Bar, 10 μm.

Mentions: The total traction force exerted on the ventral surface of a migrating fish keratocyte is ∼45 nN (Oliver et al. 1995), an order of magnitude smaller than the migration force exerted by fibroblasts (Harris et al. 1980). The predominant ventral traction forces are perpendicular to the direction of migration. These forces are ∼20 nN in size, and they produce wrinkles in deformable substratum that are parallel to the direction of migration (Fig. 1).


Keratocytes pull with similar forces on their dorsal and ventral surfaces.

Galbraith CG, Sheetz MP - J. Cell Biol. (1999)

Keratocytes generate large traction forces orthogonal to the direction of migration. Keratocytes generate forces perpendicular to the direction of migration as indicated by wrinkles that are parallel to the direction of motion. Deformable substratum were made by cross-linking Dow Corning 710 fluid. The stiffness of the substrata was decreased by exposure to 254 nm UV light (Burton and Taylor 1997). Keratocytes generate wrinkles that are parallel to the direction of motion, indicating that the largest traction forces are perpendicular to the direction of motion. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2168090&req=5

Figure 1: Keratocytes generate large traction forces orthogonal to the direction of migration. Keratocytes generate forces perpendicular to the direction of migration as indicated by wrinkles that are parallel to the direction of motion. Deformable substratum were made by cross-linking Dow Corning 710 fluid. The stiffness of the substrata was decreased by exposure to 254 nm UV light (Burton and Taylor 1997). Keratocytes generate wrinkles that are parallel to the direction of motion, indicating that the largest traction forces are perpendicular to the direction of motion. Bar, 10 μm.
Mentions: The total traction force exerted on the ventral surface of a migrating fish keratocyte is ∼45 nN (Oliver et al. 1995), an order of magnitude smaller than the migration force exerted by fibroblasts (Harris et al. 1980). The predominant ventral traction forces are perpendicular to the direction of migration. These forces are ∼20 nN in size, and they produce wrinkles in deformable substratum that are parallel to the direction of migration (Fig. 1).

Bottom Line: Borisy. 1997.Cell Biol. 139:397-415).Similar forces were generated on both the ventral (0.2 nN/microm(2)) and the dorsal (0.4 nN/microm(2)) surfaces of the lamella, suggesting that dorsal matrix contacts are as effectively linked to the force-generating cytoskeleton as ventral contacts.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.

ABSTRACT
As cells move forward, they pull rearward against extracellular matrices (ECMs), exerting traction forces. However, no rearward forces have been seen in the fish keratocyte. To address this discrepancy, we have measured the propulsive forces generated by the keratocyte lamella on both the ventral and the dorsal surfaces. On the ventral surface, a micromachined device revealed that traction forces were small and rearward directed under the lamella, changed direction in front of the nucleus, and became larger under the cell body. On the dorsal surface of the lamella, an optical gradient trap measured rearward forces generated against fibronectin-coated beads. The retrograde force exerted by the cell on the bead increased in the thickened region of the lamella where myosin condensation has been observed (Svitkina, T.M., A.B. Verkhovsky, K.M. McQuade, and G. G. Borisy. 1997. J. Cell Biol. 139:397-415). Similar forces were generated on both the ventral (0.2 nN/microm(2)) and the dorsal (0.4 nN/microm(2)) surfaces of the lamella, suggesting that dorsal matrix contacts are as effectively linked to the force-generating cytoskeleton as ventral contacts. The correlation between the level of traction force and the density of myosin suggests a model for keratocyte movement in which myosin condensation in the perinuclear region generates rearward forces in the lamella and forward forces in the cell rear.

Show MeSH
Related in: MedlinePlus