HMG-I/Y bind preferentially to the minor groove of A+T rich regions in double-stranded DNA. It is suggested that these proteins could function in nucleosome phasing and in the 3'-end processing of mRNA transcripts. They are also involved in the transcription regulation of genes containing, or in close proximity to A+T-rich regions. Interacts with HIPK2 (By similarity). Constitutively phosphorylated on two or three sites. Hyperphosphorylated at early stages of apoptosis, followed by dephosphorylation and methylation, which coincides with chromatin condensation. Isoforms HMG-I and HMG-Y can be phosphorylated by HIPK2. Phosphorylation of HMG-I at Ser-36, Thr-53 and Thr-78 and of HMG-Y at Thr-42 and Thr-67 by HIPK2 modulates DNA-binding affinity. HMG-Y is not methylated. Methylation at Arg-58 is mutually exclusive with methylation at Arg-60. With 1 acetyl and 2 phosphate groups. The measured range is 2-107. With 1 acetyl and 3 phosphate groups. The measured range is 2-107. With 1 acetyl, 1 methyl and 2 phosphate groups. The measured range is 2-107. With 1 acetyl, 1 methyl and 3 phosphate groups. The measured range is 2-107. With 1 acetyl, 2 methyl and 2 phosphate groups. The measured range is 2-107. With 1 acetyl, 2 methyl and 3 phosphate groups. The measured range is 2-107. A chromosomal aberration involving HMGA1 is found in pulmonary chondroid hamartoma. Translocation t(6;14)(p21;q23-24) with RAD51B. Belongs to the HMGA family.