Identity of nuclear high‐mobility‐group protein, HMG‐1, and sulfoglucuronyl carbohydrate‐binding protein, SBP‐1, in brain

• Published in: Journal of neurochemistry Vol. 77; no. 1; pp. 120 - 131
• Main Authors: Chou, Denise K. H., Evans, James E., Jungalwala, Firoze B.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.04.2001; Blackwell
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Carrier Proteins - chemistry; Carrier Proteins - isolation & purification; Carrier Proteins - metabolism; Carrier Proteins - pharmacology; Cells, Cultured; Cerebellum - chemistry; Cerebellum - cytology; Chromatography, High Pressure Liquid; development; Development. Senescence. Regeneration. Transplantation; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Glycolipids - metabolism; high mobility group proteins; High Mobility Group Proteins - chemistry; High Mobility Group Proteins - isolation & purification; High Mobility Group Proteins - metabolism; High Mobility Group Proteins - pharmacology; HMGB1 Protein; HNK‐1 epitope; Mass Spectrometry; Molecular Sequence Data; Molecular Weight; neural cell differentiation; neurite outgrowth; Neurites - drug effects; Protein Binding; Rats; Rats, Sprague-Dawley; Sequence Analysis, Protein; sulfoglucuronyl carbohydrate binding protein; Vertebrates: nervous system and sense organs; Vertebrata; Mammalia; Rat; Sulfoglucuronyl carbohydrate binding protein; Rodentia; Central nervous system; Development; High mobility group protein; Differentiation; Nuclear protein; Brain (vertebrata)
• DOI: 10.1046/j.1471-4159.2001.00209.x
• ISSN: 0022-3042

High‐mobility‐group (HMG) proteins are a family of non‐histone chromosomal proteins which bind to DNA. They have been implicated in multiple aspects of gene regulation and cellular differentiation. Sulfoglucuronyl carbohydrate binding protein, SBP‐1, which is also localized in the neuronal nuclei, was shown to be required for neurite outgrowth and neuronal migration during development of the nervous system. In order to establish relationship between SBP‐1 and HMG family proteins, two HMG proteins were isolated and purified from developing rat cerebellum by heparin–sepharose and sulfatide‐octyl–sepharose affinity column chromatography and their biochemical and biological properties were compared with those of SBP‐1. Characterization by high performance liquid chromatography–mass spectrometry (HPLC–MS), partial peptide sequencing and western blot analysis showed the isolated HMG proteins to be HMG‐1 and HMG‐2. Isoelectric focusing, HPLC–MS and peptide sequencing data also suggested that HMG‐1 and SBP‐1 were identical. Similar to SBP‐1, both HMG proteins bound specifically to sulfated glycolipids, sulfoglucuronylglycolipids (SGGLs), sulfatide and seminolipid in HPTLC‐immuno‐overlay and solid‐phase binding assays. The HMG proteins promoted neurite outgrowth in dissociated cerebellar cells, which was inhibited by SGGLs, anti‐Leu7 hybridoma (HNK‐1) and anti‐SBP‐1 peptide antibodies, similar to SBP‐1. The proteins also promoted neurite outgrowth in explant cultures of cerebellum. The results showed that the cerebellar HMG‐1 and ‐2 proteins have similar biochemical and biological properties and HMG‐1 is most likely identical to SBP‐1.