Disease relevance of Hypusine

• By inhibiting DHS, this compound suppresses hypusine formation and, thereby, activation of eukaryotic initiation factor 5A (eIF-5A), a cellular cofactor of the HIV-1 Rev regulatory protein [1].
• In order to investigate the conservation of this protein, we examined two nonmammalian eukaryotes, the yeast Saccharomyces cerevisiae and the insect Drosophila melanogaster, and the eubacterial prokaryote Escherichia coli for the presence of the hypusine-containing protein [2].
• In the eubacterium E. coli, one tritiated protein was predominant, but its molecular weight was 24,000 and we found no evidence that it contained tritiated hypusine [2].
• The rates of synthesis and turnover of the rare amino acid hypusine [N6-(4-amino-2-hydroxybutyl)-2,6-diaminohexanoic acid] in protein were studied in relationship to polyamine metabolism and growth rates in rat hepatoma tissue-culture (HTC) cells [3].
• NAD+ stimulated the spermidine-dependent hypusine formation on the 18 kDa protein in cytosolic lysates derived from NB-15 mouse neuroblastoma cells [4].

High impact information on Hypusine

• Maintenance by resting lymphocytes of a pool of unmodified protein and early activation during growth of the hypusine-forming enzyme system suggest that this posttranslational modification may be of importance to lymphocyte activation [5].
• Posttranslational formation of hypusine in a single major protein occurs generally in growing cells and is associated with activation of lymphocyte growth [5].
• In several other cell lines, hypusine formation was also observed in a single protein of approximately 18 kd, pI approximately 5.1, indistinguishable electrophoretically from the lymphocyte protein [5].
• Furthermore, an inhibitor of the hypusine modification, GC7 (N(1)-guanyl-1, 7-diaminoheptane), prevents CD83 surface expression by apparently interfering with nucleocytoplasmic translocation of the CD83 mRNA and, importantly, significantly inhibits DC-mediated T lymphocyte activation [6].
• In this study, we investigated the course of expression of the unique hypusine-containing protein eukaryotic initiation factor 5A (eIF-5A), which is part of a particular RNA nuclear export pathway, during in vitro generation of human DCs [6].

Chemical compound and disease context of Hypusine

• Interaction of eukaryotic initiation factor 5A with the human immunodeficiency virus type 1 Rev response element RNA and U6 snRNA requires deoxyhypusine or hypusine modification [7].

Biological context of Hypusine

• The data presented suggest that CD83 mRNA is transported from the nucleus to the cytoplasm via a specific nuclear export pathway and that hypusine formation appears to be essential for the maturation of functional DCs [6].
• Induced gene expression of the hypusine-containing protein eukaryotic initiation factor 5A in activated human T lymphocytes [8].
• Translation initiation factor 5A and its hypusine modification are essential for cell viability in the yeast Saccharomyces cerevisiae [9].
• Evidence that hypusine is implicated in cell growth prompted this study of the cellular effects of these inhibitors [10].
• Hydroxylation at this carbon atom, which constitutes the last step in hypusine biosynthesis, is the cause of bond cleavage [11].

Anatomical context of Hypusine

• Is hypusine essential for eukaryotic cell proliferation [12]?
• Changes in eIF-4D hypusine modification or abundance are not correlated with translational repression in HeLa cells [13].
• [3H]Hypusine-containing proteins from cells which had been cultured with [3H]spermidine were employed as tracers for isolation of hypusine-containing proteins from whole chick embryos [14].
• When the 3H-labeled hypusine-containing protein isolated from Chinese hamster ovary (CHO) cells that were grown with radioactive polyamine is digested with trypsin and the digest is subjected to two-dimensional separation, a single radioactive peptide is seen [15].
• Eukaryotic initiation factor 4D. Purification from human red blood cells and the sequence of amino acids around its single hypusine residue [16].

Associations of Hypusine with other chemical compounds

• The Saccharomyces cerevisiae strain with deletion of YJR070C contained only deoxyhypusine but no hypusine, indicating that YJR070C was the single DOHH gene in this organism [17].
• The hypusine-containing protein and purified eIF-4D showed identity of electrophoretic mobility in both isoelectric focusing and NaDodSO4/polyacrylamide gel electrophoresis dimensions, while eIF-4C was clearly nonidentical [18].
• Spermidine but not spermine is essential for hypusine biosynthesis and growth in Saccharomyces cerevisiae: spermine is converted to spermidine in vivo by the FMS1-amine oxidase [19].
• This finding supports the proposed mechanism in which peptide-bound lysine is converted to peptide-bound hypusine through hydroxylation of the transitory intermediate, deoxyhypusine [20].
• These findings suggest that in control Chinese hamster ovary cells and in cells containing approximately 10% of the control level of spermidine, deoxyhypusine + hypusine synthesis occurs during or immediately after eukaryotic initiation factor 4D precursor translation [21].

Gene context of Hypusine

• The export signal in eIF-5A appears to be complex and to involve the hypusine modification that is unique to eIF-5A [22].
• The TIF51A gene was altered by site-directed mutagenesis at the site of hypusination by changing the Lys codon to that for Arg, thereby producing a stable protein that retains the positive charge but is not modified to the hypusine derivative [9].
• Deoxyhypusine synthase catalyzes the first step in hypusine (N epsilon-(4-amino-2-hydroxybutyl)lysine) synthesis in a single cellular protein, eIF5A precursor [23].
• Factor eIF-4D is the only known mammalian protein that undergoes a unique post-translational modification of Lys-50 to the amino acid hypusine, and interestingly the same lysine is also present in the ANB1 gene product [24].
• IFNalpha decreased hypusine synthesis by 75%; exposure of cells to EGF for 12 h restored hypusine synthesis almost completely [25].

Analytical, diagnostic and therapeutic context of Hypusine

• The technique of thermospray high-performance liquid chromatography/mass spectrometry provided positive identification of 15N in hypusine through final separation and on-column direct analysis of this amino acid [26].
• Sequence determination and cDNA cloning of eukaryotic initiation factor 4D, the hypusine-containing protein [27].
• Amino acid analysis confirmed the presence of tritiated hypusine in each case, and silver staining of two-dimensional polyacrylamide gels demonstrated that, in yeast and fruit flies as in mammals, the protein is relatively abundant [2].
• The main form, which accounts for approximately 95% of the total eIF-5A, carries hypusine at position 50 and is amino-terminally acetylated as determined by amino acid composition analysis and electrospray ionization mass spectrometry [28].
• Here an example is shown where overexpression of the yeast HYP2 genes, coding for a hypusine-containing protein, was alternatively analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) alone or by two-dimensional (2-D) gel electrophoresis, using the narrowed pH range of 4.5-5 [29].

References