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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.


Lamellipodial morphology of a typical staurosporine-treated cell in distinct phases. Data for the same cell as in Fig. 2B–E and Supplementary Movie 3 are shown. Phase-contrast images of the cell and its outline after 32 s (red) are superimposed. (A–C) Stationary phases. Extension speeds at the leading edge showed a gradient along the leading edge. (D–E) Widening phases. Extension speeds were almost constant along the leading edge. Note that “square” corners were formed at each end of the half lamellipod without graded speed (arrow heads).
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f3-7_69: Lamellipodial morphology of a typical staurosporine-treated cell in distinct phases. Data for the same cell as in Fig. 2B–E and Supplementary Movie 3 are shown. Phase-contrast images of the cell and its outline after 32 s (red) are superimposed. (A–C) Stationary phases. Extension speeds at the leading edge showed a gradient along the leading edge. (D–E) Widening phases. Extension speeds were almost constant along the leading edge. Note that “square” corners were formed at each end of the half lamellipod without graded speed (arrow heads).

Mentions: To learn how lamellipodial enlargement occurs, lamellipodial morphologies in the two phases, “stationary” and “widening,” of the keratocytes treated with 10 nM staurosporine were compared in detail (Fig. 3). The lamellipodia in the stationary phase, locomoting with constant cell size, adopted a crescent shape typical of ordinary fan-shaped keratocytes, although they were more elongated than those of normal cells (Fig. 3A–C). Interestingly, the cells in the widening phase (Fig. 3D–F) were found to have a characteristic shape: that is, both sides of a widening lamellipod were nearly straight and perpendicular to the long arc of the leading front. “Square corners” were thus formed at both ends of the leading edge (Fig. 3D–F, arrow heads). The resulting morphology of the whole lamellipod thus resembled a part of a flat ring or a slice of Baumkuchen.


Staurosporine induces lamellipodial widening in locomoting fish keratocytes by abolishing the gradient from radial extension of leading edge
Lamellipodial morphology of a typical staurosporine-treated cell in distinct phases. Data for the same cell as in Fig. 2B–E and Supplementary Movie 3 are shown. Phase-contrast images of the cell and its outline after 32 s (red) are superimposed. (A–C) Stationary phases. Extension speeds at the leading edge showed a gradient along the leading edge. (D–E) Widening phases. Extension speeds were almost constant along the leading edge. Note that “square” corners were formed at each end of the half lamellipod without graded speed (arrow heads).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036771&req=5

f3-7_69: Lamellipodial morphology of a typical staurosporine-treated cell in distinct phases. Data for the same cell as in Fig. 2B–E and Supplementary Movie 3 are shown. Phase-contrast images of the cell and its outline after 32 s (red) are superimposed. (A–C) Stationary phases. Extension speeds at the leading edge showed a gradient along the leading edge. (D–E) Widening phases. Extension speeds were almost constant along the leading edge. Note that “square” corners were formed at each end of the half lamellipod without graded speed (arrow heads).
Mentions: To learn how lamellipodial enlargement occurs, lamellipodial morphologies in the two phases, “stationary” and “widening,” of the keratocytes treated with 10 nM staurosporine were compared in detail (Fig. 3). The lamellipodia in the stationary phase, locomoting with constant cell size, adopted a crescent shape typical of ordinary fan-shaped keratocytes, although they were more elongated than those of normal cells (Fig. 3A–C). Interestingly, the cells in the widening phase (Fig. 3D–F) were found to have a characteristic shape: that is, both sides of a widening lamellipod were nearly straight and perpendicular to the long arc of the leading front. “Square corners” were thus formed at both ends of the leading edge (Fig. 3D–F, arrow heads). The resulting morphology of the whole lamellipod thus resembled a part of a flat ring or a slice of Baumkuchen.

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.