Cross-linking of actin filaments by myosin II is a major contributor to cortical integrity and cell motility in restrictive environments
J Cell Sci
Laevsky and Knecht 116 (18): 3761.
JCS00684 Movies
Files in this Data Supplement:
Movie 1
-
(see Fig.
4) Cells lacking myosin II heavy chain were imaged under 0.5% agarose while
moving in a folate gradient. The cells were allowed to move up the folate
gradient for approximately 4 hours before imaging was started. Images were acquired
every 5 seconds and then processed to create a Quicktime™ movie (Fig. 4A). The
cells can be seen to stretch and fragment as they attempt to move up the
gradient. A magnified view of a single cells fragmenting is shown in the second
movie (4B).
Movie 2
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(seeFig. 5) The localization of F-actin in
myosin II mutant cells moving under agarose. MhcA–
cells expressing GFP-ABD120 were used to visualize F-actin filaments while
cells were moving under 0.5% agarose. The cell shown is in the process of
fragmenting. The GFP probe can be seen to accumulate in the uropod that will
eventually be lost when the cell fragments. This loss of actin from the cell
may explain why they eventually cease moving up the gradient.
Movie 3
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(seeFig. 6) The movement of myosin II mutant
cells at the edge of a 2% agarose trough. MhcA– cells
do not move out of troughs when the concentration of agarose is 1% or above.
Cells were visualized by time lapse imaging at 5 second intervals near the
trough edge. The movie shows the cells moving back and forth along the trough
edge, periodically protruding a pseudopod underneath the agarose. However,
unlike wild-type cells, the cell body of the myosin mutants is never able to
flatten and continue to move up the gradient under the agarose.
Movie 4
-
(see Fig.
7) The localization of myosin and F-actin in wild-type and mlcE–
mutant cells moving under agarose. Both wild-type cells and mutants lacking the
essential light chain (mELC) are able to move under agarose. In order to
examine the cytoskeletal structure, cells expressing either GFP-ABD120 or
GFP-myosin II were imaged while moving under agarose. The folate gradient was
established using a glass bottom Petri dish (Willco Wells) and the cells were
imaged at 5 second intervals by confocal microscopy using a 100´ oil immersion lens. Wild type and mlcE– cells show a similar dynamic
distribution of myosin and F-actin while moving under agarose.