MATURATION OF CELL-SUBSTRATUM FOCAL ADHESIONS INDUCED BY DEPOLYMERIZATION OF MICROTUBULES IS MEDIATED BY INCREASED CORTICAL TENSION

Citation
Oj. Pletjushkina et al., MATURATION OF CELL-SUBSTRATUM FOCAL ADHESIONS INDUCED BY DEPOLYMERIZATION OF MICROTUBULES IS MEDIATED BY INCREASED CORTICAL TENSION, Cell adhesion and communication, 5(2), 1998, pp. 121-135
Citations number
48
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell Biology",Biology
Journal title
ISSN journal
1061-5385
Volume
5
Issue
2
Year of publication
1998
Pages
121 - 135
Database
ISI
SICI code
1061-5385(1998)5:2<121:MOCFAI>2.0.ZU;2-R
Abstract
Dynamics of alterations of focal adhesions (FA) induced by a microtubu le-depolymerizing drug, colcemid, was examined in several types of fib roblastic cells. Evolution of individual FA in cultured cells was moni tored by interference-reflection microscopy (IRM); at the end of the m onitoring period (3 hours) the cells were fixed and immunofluorescence microscopy of the same FA was performed with an antibody against vinc ulin. Control and colcemid-treated cells remained non-motile and did n ot show lamellipodial activity at the edges. During the incubation, fo rmation of new FA or disappearance of pre-existing FA did not occur in either colcemid-treated or control cultures. However, FA in colcemid- treated cells significantly increased in size in the course of a 3 hou r incubation. The growth of FA was centripetal and sometimes was accom panied by the fusion of several adjacent FA. Immunofluorescence examin ation showed that colcemid-induced growth of FA was accompanied by acc umulation of several proteins specific for these structures including vinculin, talin, paxillin and pp125FAK kinase. Immunoblotting with ant i-vinculin antibody showed that incubation with colcemid considerably increased the amount of vinculin associated with the ventral membranes due to its partial redistribution from a soluble pool into the growin g adhesions. A substantial increase in tyrosine phosphorylation of pp1 25FAK was also observed in colcemid-treated cells. In cells plated on elastic silicone rubber films, colcemid induced formation of wrinkles in the films and these wrinkles relaxed after treatment with cytochala sin D. These results confirm that microtubule depolymerization increas es traction transmitted to the substratum by the actin cortex and show s that an increase in cortical tension accompanies maturation of FA. T aken together, these data show that short-term incubation with colcemi d does not affect the formation of initial FA, In contrast, microtubul e depolymerization considerably stimulates the maturation FA, manifest ed by their centripetal growth. Maturation is proposed to be mediated by increased cortical tension, which is caused by microtubule depolyme rization.