HMGB4 is HMG2 like, isoform 2, high-mobility group box 4. This gene can be found on Chromosome 1. HMGB4 contains two HMG-box regions, which is found in a variety of eukaryotic chromosomal proteins and transcription. HMGB proteins are phosphorylated to various extents reveals that the existence of differentially modified forms increases the number of distinct HMGB protein variants in plant chromatin that may be adapted to certain functions.