Skip to main page content
U.S. flag

An official website of the United States government

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1983 Dec;97(6):1918-24.
doi: 10.1083/jcb.97.6.1918.

Microinjection of Ca++-calmodulin causes a localized depolymerization of microtubules

Microinjection of Ca++-calmodulin causes a localized depolymerization of microtubules

C Keith et al. J Cell Biol. 1983 Dec.

Abstract

The microinjection of calcium-saturated calmodulin into living fibroblasts causes the rapid disruption of microtubules and stress fibers in a sharply delimited region concentric with the injection site. This effect is specific to the calcium-bearing form of calmodulin; neither calcium-free calmodulin nor calcium ion at similar levels affects the cytoskeleton. If cells have previously been microinjected with calcium-free calmodulin, elevation of their intracellular calcium levels to 25 mM potentiates the disruption of microtubules throughout the cytoplasm. Approximately 400 mM free calcium is required to cause an equivalent disruption in uninjected cells. The level of calmodulin necessary to disrupt the full complement of cellular microtubules is found to be approximately in 2:1 molar ratio to tubulin dimer. These results indicate that calmodulin can be localized within the cytoplasm in a calcium-dependent manner and that it can act to regulate the calcium lability of microtubules at molar ratios that could be achieved locally within the cell. Our results are consistent with the hypothesis that calmodulin may be controlling microtubule polymerization equilibria in areas of high local concentration such as the mitotic spindle.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Science. 1972 Sep 22;177(4054):1104-5 - PubMed
    1. J Neurosci. 1983 Jul;3(7):1488-94 - PubMed
    1. Neurobiology. 1973;3(3):162-73 - PubMed
    1. Proc Natl Acad Sci U S A. 1975 May;72(5):1858-62 - PubMed
    1. Proc Natl Acad Sci U S A. 1976 Feb;73(2):366-70 - PubMed

Publication types