Related Experiment Video
Updated: May 30, 2026

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
Protein kinase A-mediated serine 35 phosphorylation dissociates histone H1.4 from mitotic chromosome
Chi-Shuen Chu1, Pang-Hung Hsu2, Pei-Wen Lo3
1Institute of Molecular Medicine, National Taiwan University, Taipei 100, Taiwan; Genomics Research Center, Academia Sinica, Taipei 115, Taiwan.
Abstract:
Global histone H1 phosphorylation correlates with cell cycle progression. However, the function of site-specific H1 variant phosphorylation remains unclear. Our mass spectrometry analysis revealed a novel N-terminal phosphorylation of the major H1 variant H1.4 at serine 35 (H1.4S35ph), which accumulates at mitosis immediately after H3 phosphorylation at serine 10. Protein kinase A (PKA) was found to be a kinase for H1.4S35. Importantly, Ser-35-phosphorylated H1.4 dissociates from mitotic chromatin. Moreover, H1.4S35A substitution mutant cannot efficiently rescue the mitotic defect following H1.4 depletion, and inhibition of PKA activity increases the mitotic chromatin compaction depending on H1.4. Our results not only indicate that PKA-mediated H1.4S35 phosphorylation dissociates H1.4 from mitotic chromatin but also suggest that this phosphorylation is necessary for specific mitotic functions.
Related Concept Videos
Phosphorylation
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Histone Modification
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Histone Modification
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Separation of Sister Chromatids
At the onset of anaphase, separase, a proteolytic enzyme, is...
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Spreading of Chromatin Modifications
Writers
The writer is an enzyme that can...
