Nucleation of microtubules from mitotic centrosomes is modulated by a phosphorylated epitope

At the onset of mitosis a class of proteins appears that possess a phosphorylated epitope recognized by the monoclonal antibody MPM-2. Immunofluorescence staining shows that a subset of these proteins is associated with the centrosomes of the mitotic apparatus. The appearance of these proteins coinc...

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Bibliographic Details
Published inJournal of cell science Vol. 95; no. 3; pp. 405 - 411
Main Authors CENTONZE, V. E, BORISY, G. G
Format Journal Article
LanguageEnglish
Published Cambridge Company of Biologists 01.03.1990
Subjects
Animals
Biological and medical sciences
Cell cycle, cell proliferation
Cell physiology
Cells, Cultured
centrosomes
characterization
chromosomes
Cricetinae
Cricetulus
Cytoskeleton - physiology
Cytoskeleton - ultrastructure
Epitopes - immunology
Female
Fluorescent Antibody Technique
Fundamental and applied biological sciences. Psychology
induction
interaction
Microscopy, Phase-Contrast
microtubules
Microtubules - physiology
Mitosis - immunology
Molecular and cellular biology
nucleation
Ovary - cytology
Phosphorylation
proteins
Cell culture
Vertebrata
Phosphorylation
Regulation(control)
Mammalia
Antigenic determinant
Ultrastructure
Rodentia
Microtubule
Immunofluorescence
Centrosome
Hamster
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Summary:At the onset of mitosis a class of proteins appears that possess a phosphorylated epitope recognized by the monoclonal antibody MPM-2. Immunofluorescence staining shows that a subset of these proteins is associated with the centrosomes of the mitotic apparatus. The appearance of these proteins coincides with the increased microtubule nucleating capacity of the centrosomes. We have tested whether growth of microtubules from mitotic centrosomes in a lysed cell model is dependent on the availability of the phosphorylated epitope by blocking the epitope with a specific antibody or by modifying it by removal of the phosphate. Centrosomes incubated with purified tubulin nucleate microtubule asters. However, preincubating the centrosomes with MPM-2 blocks all microtubule nucleation. Pretreating mitotic centrosomes with alkaline phosphatase also inhibits nucleation. These data suggest that the phosphorylated epitope recognized by MPM-2 is important for microtubule nucleation.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
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ISSN:0021-9533
1477-9137
DOI:10.1242/jcs.95.3.405