Abstract
Indirect immunofluorescence was used to determine the distribution of calmodulin in the mitotic apparatus of rat kangaroo PtK2 and Chinese hamster ovary (CHO) cells. The distribution of calmodulin in PtK2 cells was compared to the distribution of tubulin, also as revealed by indirect immunofluorescence. During mitosis, calmodulin was found to be a dynamic component of the mitotic apparatus. Calmodulin first appeared in association with the forming mitotic apparatus during midprophase. In metaphase and anaphase, calmodulin was found between the spindle poles and the chromosomes. While tubulin was found in the interzonal region throughout anaphase, calmodulin appeared in the interzone region only at late anaphase. The interzonal calmodulin of late anaphase condensed during telophase into two small regions, one on each side of the midbody. Calmodulin was not detected in the cleavage furrow. In view of the differences in the localization of calmodulin, tubulin, and actin in the mitotic apparatus, experiments were designed to determine the effects of various antimitotic drugs on calmodulin localization. Cytochalasin B, an inhibitor of actin microfilaments, had no apparent effect on calmodulin or tubulin localization in the mitotic apparatus of CHO cells. Microtubule inhibitors, such as colcemid and N2O, altered the appearance of tubulin- and calmodulin-specific fluorescence in mitotic CHO cells. Cold temperature (0 degrees C) altered tubulin- specific fluorescence of metaphase PtK2 cells but did not alter calmodulin-specific fluorescence. From these studies, it is concluded that calmodulin is more closely associated with the kinetichore-to-pole microtubules than other components of the mitotic apparatus.
Full Text
The Full Text of this article is available as a PDF (3.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brostrom C. O., Huang Y. C., Breckenridge B. M., Wolff D. J. Identification of a calcium-binding protein as a calcium-dependent regulator of brain adenylate cyclase. Proc Natl Acad Sci U S A. 1975 Jan;72(1):64–68. doi: 10.1073/pnas.72.1.64. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dedman J. R., Jackson R. L., Schreiber W. E., Means A. R. Sequence homology of the Ca2+-dependent regulator of cyclic nucleotide phosphodiesterase from rat testis with other Ca2+-binding proteins. J Biol Chem. 1978 Jan 25;253(2):343–346. [PubMed] [Google Scholar]
- Dedman J. R., Welsh M. J., Means A. R. Ca2+-dependent regulator. Production and characterization of a monospecific antibody. J Biol Chem. 1978 Oct 25;253(20):7515–7521. [PubMed] [Google Scholar]
- Fuller G. M., Brinkley B. R., Boughter J. M. Immunofluorescence of mitotic spindles by using monospecific antibody against bovine brain tubulin. Science. 1975 Mar 14;187(4180):948–950. doi: 10.1126/science.1096300. [DOI] [PubMed] [Google Scholar]
- Fuseler J. W. Temperature dependence of anaphase chromosome velocity and microtubule depolymerization. J Cell Biol. 1975 Dec;67(3):789–800. doi: 10.1083/jcb.67.3.789. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Herman I. M., Pollard T. D. Actin localization in fixed dividing cells stained with fluorescent heavy meromyosin. Exp Cell Res. 1978 Jun;114(1):15–25. doi: 10.1016/0014-4827(78)90030-7. [DOI] [PubMed] [Google Scholar]
- Luthra M. G., Au K. S., Hanahan D. J. Purification of an activator of human erythrocyte membrane (Ca2++Mg2+)ATPase. Biochem Biophys Res Commun. 1977 Jul 25;77(2):678–687. doi: 10.1016/s0006-291x(77)80032-6. [DOI] [PubMed] [Google Scholar]
- Marcum J. M., Dedman J. R., Brinkley B. R., Means A. R. Control of microtubule assembly-disassembly by calcium-dependent regulator protein. Proc Natl Acad Sci U S A. 1978 Aug;75(8):3771–3775. doi: 10.1073/pnas.75.8.3771. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mazia D., Petzelt C., Williams R. O., Meza I. A Ca-activated ATPase in the mitotic apparatus of the sea urchin egg (isolated by a new method). Exp Cell Res. 1972 Feb;70(2):325–332. doi: 10.1016/0014-4827(72)90143-7. [DOI] [PubMed] [Google Scholar]
- Sanger J. W. Changing patterns of actin localization during cell division. Proc Natl Acad Sci U S A. 1975 May;72(5):1913–1916. doi: 10.1073/pnas.72.5.1913. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schloss J. A., Milsted A., Goldman R. D. Myosin subfragment binding for the localization of actin-like microfilaments in cultured cells. A light and electron microscope study. J Cell Biol. 1977 Sep;74(3):794–815. doi: 10.1083/jcb.74.3.794. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Welsh M. J., Dedman J. R., Brinkley B. R., Means A. R. Calcium-dependent regulator protein: localization in mitotic apparatus of eukaryotic cells. Proc Natl Acad Sci U S A. 1978 Apr;75(4):1867–1871. doi: 10.1073/pnas.75.4.1867. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wessells N. K., Spooner B. S., Ash J. F., Bradley M. O., Luduena M. A., Taylor E. L., Wrenn J. T., Yamada K. Microfilaments in cellular and developmental processes. Science. 1971 Jan 15;171(3967):135–143. doi: 10.1126/science.171.3967.135. [DOI] [PubMed] [Google Scholar]