MICROTUBULES ARE NECESSARY FOR LAMELLAE RETRACTION OF VERO CELLS
E. A. Dobrinskikh,1,* I. A. Vorobjev 2
1 Cell Biology and Histology Department, Moscow State University, Biological Faculty,
and 2 Cell Motility Laboratory, A. N. Belozersky Institute, Moscow;
* e-mail: eadobrinsk@mail.ru
Behavior of Vero cells under the 2,3-butaneodione monoxime (BDM) treatment was examined using videomicroscopy
with contrast enhancement. After addition of BDM to the culture medium the area of cell contact with substratum
gradually reduced - within 5 min of treatment cell lamellae became thicker, after 60 min the cell area decreased ~
70 %, and the cells became nearly rounded. At the same time actin bundles (stress fibers) depolymerized, and
microtubule network became denser. Partial depolymerization of microfilaments by treatment with latrunculin B at a
concentration of 5 nM resulted in complete loss of stress fibers, yet cells slightly change their form, and
microtubule system remained the same as in the control cells. However, after addition of BDM in the presence of
latrunculin B cells retracted their lamellae more quickly then under BDM sole treatment. To evaluate the role of
microtubules in the process of cell retraction we depolymerized them with nocodazole taken at the concentration of 5
ng/ml. Under nocodazole treatment the cell area decreased ~ 20 %, and stress fibers became more thick and abandon.
The cells did not change their form, and stress fibers depolymerized very slowly under BDM treatment in the absence
of microtubules. After 1 h of BDM treatment in the presence of nocodazole stress fibers were still more numerous than
in the control cells. Complete depolymerization of stress fibers happened in 90 % of cells only in 24 h after
addition of BDM. When nocodazole had been washed out of the culture medium in the presence of BDM, lamellae started
shrinking in 6 min. This time corresponds to the time required for the partial restoration of microtubule system. On
the bases of the results obtained we conclude that retraction of the lamellae in Vero cells is guided rather mainly
by microtubules, than stress-fibers.
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