ISSN:
0886-1544
Keywords:
calcium
;
Ca2+
;
shape change
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
When flagellates of Physarum polycephalum were treated with Triton X-100 and more than 10-5 M Ca2+, the microfilamentous cytoskeleton disintegrated, as seen by staining with rhodamine-phalloidin, and myxamoebal fragmin became associated with the Triton-insoluble cytoskeleton as demonstrated by immunofluorescence microscopy and immunoblotting. The association of myxamoebal fragmin with the cytoskeleton was reversed by the subsequent addition of excess EGTA. When flagellates were permeabilized in the absence of Ca2+, myxamoebal fragmin did not associate with the cytoskeleton and diffused out of the cells. Subsequent treatment of these cells with Ca2+ was ineffective in inducing either the association of myxamoebal fragmin with the cytoskeleton or the disintegration of the microfilamentous cytoskeleton. However, treatment of these permeabilized flagellates with 10 μg/ml purified myxamoebal fragmin and 1 mM Ca2+ caused the disintegration of the microfilaments. Therefore, we conclude that myxamoebal fragmin participates in the Ca2+-induced disintegration of the microfilamentous cytoskeleton in these permeabilized cells. Rapid cooling of flagellates caused the reversible association of myxamoebal fragmin with the Triton-insoluble cytoskeleton in vivo. Thus myxamoebal fragmin may also participate in the reorganization of the microfilamentous cytoskeleton induced in vivo by the cold treatment.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cm.970100308
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