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Staurosporine induces lamellipodial widening in locomoting fish keratocytes by abolishing the gradient from radial extension of leading edge

View Article: PubMed Central - PubMed

ABSTRACT

Fish epidermal keratocytes locomote along surfaces without overall cell size or shape changes, as kinematically described by the graded radial extension (GRE) model. We found that the cell size increased during locomotion after the addition of a low dose of staurosporine or K-252a, broad-spectrum protein-serine/threonine kinase inhibitors. Quantitative shape analysis showed that the cell size increase resulted from an increase in lamellipodial width, the maximal length perpendicular to the direction of the cell locomotion, whereas the lamellipodial length, along the locomotion direction, remained constant. Importantly, the gradient of radial extension in the leading edge disappeared during lamellipodial width increase. These results suggest that a special mechanism for producing graded radial extension of lamellipodia exists to keep cell size constant, and that a protein-serine/threonine kinase plays an important role in regulating this mechanism.

No MeSH data available.


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Lamellipodial enlargement induced by treatment with 10 nM staurosporine. (A) A merged phase-contrast image from three consecutive images of Supplementary Movie 2, separated by 200-s intervals (in the order of red, green and blue). (B) A phase-contrast image of a typical cell (Supplementary Movie 3) 10 s after addition of staurosporine. (C) An image of the same cell 634 s after addition. (D) Sequential cell outlines separated by 16-s intervals, colored from blue to red to represent time (10–634 s) after addition of staurosporine. Phase-contrast images B and C are scaled to match to the outlines in D. (E) Changes in area (plotted in red), instantaneous velocity (green), maximal width (magenta) and mean length (blue) of the lamellipod of the same cell as illustrated in panels B, C and D. Time points, a–f on the area plot are correspond to those in the panels in Figure 3.
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f2-7_69: Lamellipodial enlargement induced by treatment with 10 nM staurosporine. (A) A merged phase-contrast image from three consecutive images of Supplementary Movie 2, separated by 200-s intervals (in the order of red, green and blue). (B) A phase-contrast image of a typical cell (Supplementary Movie 3) 10 s after addition of staurosporine. (C) An image of the same cell 634 s after addition. (D) Sequential cell outlines separated by 16-s intervals, colored from blue to red to represent time (10–634 s) after addition of staurosporine. Phase-contrast images B and C are scaled to match to the outlines in D. (E) Changes in area (plotted in red), instantaneous velocity (green), maximal width (magenta) and mean length (blue) of the lamellipod of the same cell as illustrated in panels B, C and D. Time points, a–f on the area plot are correspond to those in the panels in Figure 3.

Mentions: On the other hand, treatment of goldfish keratocytes with lower concentrations (10–20 nM) of staurosporine did not induce any lamellipodial fragmentation or cytoplast formation. To our surprise, the treatment instead induced a dramatic increase in cell size in almost all the fan-shaped locomoting cells (Fig. 2A–D, Supplementary Movie 2, 3). Under our experimental condition, most keratocytes showed a fan shaped morphology and high motility, whereas about 10% of keratocytes showed less-polarized fibroblast-like shapes and poor locomotion. Since the cell size increase on addition of staurosporine was not observed in these poorly motile cells, the enlargement of cells appeared to be related to cell locomotion.


Staurosporine induces lamellipodial widening in locomoting fish keratocytes by abolishing the gradient from radial extension of leading edge
Lamellipodial enlargement induced by treatment with 10 nM staurosporine. (A) A merged phase-contrast image from three consecutive images of Supplementary Movie 2, separated by 200-s intervals (in the order of red, green and blue). (B) A phase-contrast image of a typical cell (Supplementary Movie 3) 10 s after addition of staurosporine. (C) An image of the same cell 634 s after addition. (D) Sequential cell outlines separated by 16-s intervals, colored from blue to red to represent time (10–634 s) after addition of staurosporine. Phase-contrast images B and C are scaled to match to the outlines in D. (E) Changes in area (plotted in red), instantaneous velocity (green), maximal width (magenta) and mean length (blue) of the lamellipod of the same cell as illustrated in panels B, C and D. Time points, a–f on the area plot are correspond to those in the panels in Figure 3.
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Related In: Results  -  Collection

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f2-7_69: Lamellipodial enlargement induced by treatment with 10 nM staurosporine. (A) A merged phase-contrast image from three consecutive images of Supplementary Movie 2, separated by 200-s intervals (in the order of red, green and blue). (B) A phase-contrast image of a typical cell (Supplementary Movie 3) 10 s after addition of staurosporine. (C) An image of the same cell 634 s after addition. (D) Sequential cell outlines separated by 16-s intervals, colored from blue to red to represent time (10–634 s) after addition of staurosporine. Phase-contrast images B and C are scaled to match to the outlines in D. (E) Changes in area (plotted in red), instantaneous velocity (green), maximal width (magenta) and mean length (blue) of the lamellipod of the same cell as illustrated in panels B, C and D. Time points, a–f on the area plot are correspond to those in the panels in Figure 3.
Mentions: On the other hand, treatment of goldfish keratocytes with lower concentrations (10–20 nM) of staurosporine did not induce any lamellipodial fragmentation or cytoplast formation. To our surprise, the treatment instead induced a dramatic increase in cell size in almost all the fan-shaped locomoting cells (Fig. 2A–D, Supplementary Movie 2, 3). Under our experimental condition, most keratocytes showed a fan shaped morphology and high motility, whereas about 10% of keratocytes showed less-polarized fibroblast-like shapes and poor locomotion. Since the cell size increase on addition of staurosporine was not observed in these poorly motile cells, the enlargement of cells appeared to be related to cell locomotion.

View Article: PubMed Central - PubMed

ABSTRACT

Fish epidermal keratocytes locomote along surfaces without overall cell size or shape changes, as kinematically described by the graded radial extension (GRE) model. We found that the cell size increased during locomotion after the addition of a low dose of staurosporine or K-252a, broad-spectrum protein-serine/threonine kinase inhibitors. Quantitative shape analysis showed that the cell size increase resulted from an increase in lamellipodial width, the maximal length perpendicular to the direction of the cell locomotion, whereas the lamellipodial length, along the locomotion direction, remained constant. Importantly, the gradient of radial extension in the leading edge disappeared during lamellipodial width increase. These results suggest that a special mechanism for producing graded radial extension of lamellipodia exists to keep cell size constant, and that a protein-serine/threonine kinase plays an important role in regulating this mechanism.

No MeSH data available.


Related in: MedlinePlus