A cdc2-like kinase phosphorylates histone H1 in the amitotic macronucleus of Tetrahymena

Roth, S. Y., Collini, M. P., Draetta, G., Beach, D., Allis, C. D. (August 1991) A cdc2-like kinase phosphorylates histone H1 in the amitotic macronucleus of Tetrahymena. EMBO J, 10 (8). pp. 2069-75. ISSN 0261-4189 (Print)0261-4189 (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/2065655

Abstract

Genetic and biochemical studies have shown that cdc2 protein kinase plays a pivotal role in a highly conserved mechanism controlling the entry of cells into mitosis. It is generally believed that one function of cdc2 kinase is to phosphorylate histone H1 which in turn promotes mitotic chromosome condensation. However, direct evidence linking H1 phosphorylation to mitotic chromatin condensation is limited and the exact cellular function(s) of H1 phosphorylation remains unclear. In this study, we show that mammalian cdc2 kinase phosphorylates H1 from the amitotic macronucleus of Tetrahymena with remarkable fidelity. Furthermore, we demonstrate that macronuclei from Tetrahymena contain a growth-associated H1 kinase activity which closely resembles cdc2 kinase from other eukaryotes. Using polyclonal antibodies raised against yeast p34cdc2, we have detected a 36 kd immunoactive polypeptide in macronuclei which binds to Suc1 (p13)-coated beads and closely follows H1 kinase activity. Since macronuclei divide without mitotic chromosome condensation, these data demonstrate that H1 phosphorylation by cdc2 kinase may be necessary, but is not sufficient to promote mitotic chromatin condensation. The fact that an activity which strongly resembles mammalian cdc2 kinase is active during cell growth in a nucleus which does not undergo mitosis and chromosome condensation suggests that other factors are needed for a true mitotic division to occur. These data also reinforce the notion that H1 phosphorylation has important functions outside mitosis both in Tetrahymena and in mammalian cells.

Item Type: Paper
Uncontrolled Keywords: Animals Blotting, Western CDC2 Protein Kinase/*metabolism Cell Nucleus/*enzymology Electrophoresis, Polyacrylamide Gel HeLa Cells Histones/*metabolism Humans Immunohistochemistry Mitosis Phosphorylation Substrate Specificity Tetrahymena/cytology/*metabolism
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > cdc2
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > histone
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > kinase
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression > phosphorylation
CSHL Authors:
Communities: CSHL labs > Beach lab
Depositing User: Matt Covey
Date: August 1991
Date Deposited: 13 Jan 2016 19:38
Last Modified: 13 Jan 2016 19:38
PMCID: PMC452890
URI: http://repository.cshl.edu/id/eprint/32047

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