Differential phosphorylation of nuclear nonhistone high mobility group proteins HMG 14 and HMG 17 during the cell cycle.
The phosphorylation of the high-mobility group (HMG) proteins at different stages of the cell cycle was studied in synchronized HeLa cells. HMG proteins were extracted and analyzed by NaDodSO4/polyacrylamide gel electrophoresis. Although the molecular weight distribution of HMGs remains unchanged, their total amounts increase by as much as 20-25% in the G1 and S phases when compared with amounts in G2. However, the most significant finding is that there is a 7-fold increase of 32P incorporation into HMG 14 in the G2 phase compared with that in G1, and a 2-fold increase of 32P incorporation into HMG 17 in early S phase relative to the incorporation in the G1 and G2 stages. In contrast, HMG 1 and HMG 2 are not phosphorylated. The clear demonstration of differential phosphorylation of HMG 14 and 17 at specific stages of the cell cycle warrants a serious consideration of their role in tissue-specific maintenance of the altered chromatin structure characteristic of potentially active or actively transcribed chromatin domains.
D002453:Cell Cycle; D002467:Cell Nucleus / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D006367:HeLa Cells / Q000502:physiology; D006609:High Mobility Group Proteins; D006801:Humans; D007700:Kinetics; D008970:Molecular Weight; D010766:Phosphorylation
D002868:Chromosomal Proteins, Non-Histone; D006609:High Mobility Group Proteins