Binds to the inner side of the nucleosomal DNA thus altering the interaction between the DNA and the histone octamer. May be involved in the process which maintains transcribable genes in a unique chromatin conformation. Inhibits the phosphorylation of nucleosomal histones H3 and H2A by RPS6KA5/MSK1 and RPS6KA3/RSK2. Interacts with transcriptional regulator SEHBP. Cytoplasmic enrichment upon phosphorylation. Phosphorylation favors cytoplasmic localization (By similarity). Phosphorylation on Ser-20 and Ser-24 weakens binding to nucleosomes and increases the rate of H3 phosphorylation. Belongs to the HMGN family.