Abstracts of papers (2010)
Last Update: 02/09/2011
Abstracts of papers (2010)
[2010-1] Igarashi, K., and Kashiwagi, K., Int. J. Biochem. Cell Biol. 42, 39-51 (2010)
Polyamines (putrescine, spermidine and spermine) are essential for normal
cell growth. The polyamine levels in cells are regulated by biosynthesis,
degradation, and transport. Polyamines can modulate the functions of DNA,
nucleotide triphosphates, proteins, and especially RNA because most polyamines
exist in a polyamine-RNA complex in cells. Thus, the major focus on this
review is on the role of polyamines in protein synthesis. In addition,
effects of polyamines on B to Z conversion of DNA, transcription, phosphorylation
of proteins, cell cycle progression, apoptosis and ion channels, especially
NMDA receptors, are outlined. The function of eIF5A is also briefly discussed.
Finally, a correlation between acrolein, produced from polyamines by polyamine
oxidases, and chronic renal failure or brain stroke is summarized. Increased
levels of polyamine oxidases and acrolein are good markers of chronic renal
failure and brain stroke.
[2010-2] Yoshida, M. et al., Biochem. Biophys. Res. Commun. 391, 1234-1239 (2010)
It is known that the level of protein-conjugated acrolein in plasma is
a good marker of chronic renal failure and brain infarction. Thus, studies
were carried out to determine which kinds of plasma proteins are conjugated
with acrolein. It was found that acrolein was mainly conjugated with albumin.
Tandem mass spectrometry analysis demonstrated that Lys-557 and Lys-560,
located at the surface of domain III of albumin, were the major sites conjugated
with acrolein. This is the first report to identify the amino acid residues
in a protein modified by acrolein in vivo. It was found that conjugation
of acrolein with albumin contributed to a decrease in the toxicity of acrolein.
[2010-3] Higashi, K. et al., Clin. Chim. Acta 411, 359-363 (2010)
Background: We recently found that an increased plasma concentration of protein-conjugated
acrolein is a good biomarker for stroke. Therefore we determine whether
the concentration of protein-conjugated acrolein is increased in saliva
from patients with primary Sjögren's syndrome.
Methods: Stimulated whole-mixed saliva was collected from 10 patients and 13 control subjects. The concentration of protein-conjugated acrolein in saliva and plasma was measured by either Western blotting or enzyme-linked immunosorbent assay.
Results: The concentration of protein-conjugated acrolein, especially albumin-conjugated acrolein, was greatly increased in saliva from patients with primary Sjögren's syndrome (p < 0.001). The concentration of protein-conjugated acrolein was inversely correlated with the flow rate of saliva.
Conclusion: The results indicate that the concentration of protein-conjugated acrolein,
a marker of cell or tissue damage, in saliva is well correlated with seriousness
of primary Sjögren's syndrome.
[2010-4] Shiokawa, K. et al., Amino Acids 38, 439-449 (2010)
We have been studying control mechanisms of gene expression in early embryogenesis
in a South African clawed toad Xenopus laevis, especially during the period of midblastula transition (MBT), or the
transition from the phase of active cell division (cleavage stage) to the
phase of extensive morphogenesis (post-blastular stages). We first found
that ribosomal RNA synthesis is initiated shortly after MBT in Xenopus embryos and those weak bases, such as amines and ammonium ion, selectively inhibit the initiation and subsequent activation of rRNA synthesis. We then found that rapidly labeled heterogeneous mRNA-like RNA is synthesized in embryos at pre-MBT stage. We then performed cloning and expression studies of several genes, such as those for activin receptors, follistatin and aldolases, and then reached the studies of S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in polyamine metabolism.
Here, we cloned a Xenopus SAMDC cDNA and performed experiments to overexpress the in vitro-synthesized
SAMDC mRNA in Xenopus early embryos, and found that the maternally preset program of apoptosis occurs in cleavage stage embryos, which is executed when embryos reach the stage of MBT. In the present article, we first summarize results on SAMDC and the maternal program of apoptosis, and then describe our studies on small-molecular-weight substances like polyamines, amino acids, and amines in Xenopus embryos. Finally, we summarize our studies on weak bases, especially on
ammonium ion, as the specific inhibitor of ribosomal RNA synthesis in Xenopus embryonic cells.
[2010-5] Park, M. H. et al., Amino Acids 38, 491-500 (2010)
The unusual basic amino acid, hypusine [N(epsilon)-(4-amino-2-hydroxybutyl)-lysine],
is a modified lysine with the addition of the 4-aminobutyl moiety from
the polyamine spermidine. This naturally occurring amino acid is a product
of a unique posttranslational modification that occurs in only one cellular
protein, eukaryotic translation initiation factor 5A (eIF5A, eIF-5A). Hypusine
is synthesized exclusively in this protein by two sequential enzymatic
steps involving deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase
(DOHH). The deoxyhypusine/hypusine synthetic pathway has evolved in archaea
and eukaryotes, and eIF5A, DHS and DOHH are highly conserved suggesting
a vital cellular function of eIF5A. Gene disruption and mutation studies
in yeast and higher eukaryotes have provided valuable information on the
essential nature of eIF5A and the deoxyhypusine/hypusine modification in
cell growth and in protein synthesis. In view of the extraordinary specificity
and functional significance of hypusine-containing eIF5A in mammalian cell
proliferation, eIF5A and the hypusine biosynthetic enzymes are novel potential
targets for intervention in aberrant cell proliferation.
[2010-6] Igarashi, K. and Kashiwagi, K., Plant. Physiol. Biochem. 48, 506-512 (2010)
Polyamine content in cells is regulated by biosynthesis, degradation and
transport. In Escherichia coli, there are two polyamine uptake systems, namely spermidine-preferential (PotABCD) and putrescine-specific (PotFGHI), which belong to the family of ATP binding cassette transporters. Putrescine-ornithine and cadaverine-lysine antiporters, PotE and CadB, each consisting of 12 transmembrane segments, are important for cell growth at acidic pH. Spermidine excretion protein (MdtJI) was also recently identified. When putrescine was used as energy source, PuuP functioned as a putrescine transporter. In Saccharomyces cerevisiae, there are four kinds of polyamine uptake proteins (DUR3, SAM3, GAP1 and AGP2), consisting of either 12 or 16 transmembrane segments. Among them, DUR3 and SAM3 mostly contribute to polyamine uptake. There are also five kinds of polyamine excretion proteins (TPO1-5), consisting of 12 transmembrane segments. Among them, TPO1 and TPO5 are the most active proteins. Since a polyamine metabolizing enzyme, spermidine/spermine N1-acetyltransferase, is not present in yeast, five kinds of excretion proteins may exist. The current status of polyamine transport in mammalian and plant cells are reviewed.
[2010-7] Togashi, M. et al., Org. Lett. 12, 1704-1707 (2010)
A novel lanthanide probe was designed, synthesized, and employed for a sensitive and reliable assay of acrolein based on time-resolved luminescence measurement, which suppresses the background signal of serum.
[2010-8] Yoshida, M. et al., Atherosclerosis 211, 475-479 (2010)
Objective: We found previously that the measurement of plasma levels of protein-conjugated
acrolein (PC-Acro) together with IL-6 and CRP can be used to identify silent
brain infarction (SBI) with high sensitivity and specificity. The aim of
this study was to clarify how three biochemical markers are correlated
to SBI, carotid atherosclerosis (CA) and white matter hyperintensity (WMH).
Methods: The levels of PC-Acro, IL-6 and CRP in plasma were measured by ELISA.
SBI and WMH were evaluated by MRI, and CA was evaluated by duplex carotid
ultrasonography.
Results: A total of 790 apparently healthy volunteers were classified into 260
control, 214 SBI, 263 CA and 245 WMH subjects, which included 187 subjects
with two or three pathologies. When the combined measurements of PC-Acro,
IL-6 and CRP were evaluated together with age, using a receiver operating
characteristic curve and artificial neural networks, the relative risk
value (RRV), an indicator of tissue damage, was in the order SBI with CA
(0.90)>SBI (0.80)>CA (0.76)>WMH with CA (0.65)>WMH (0.46)>control
(0.14). RRV was also correlated with severity in each group of SBI, CA
and WMH.
Conclusion: The RRV supports the idea that the degree of risk to develop a stroke
is in the order SBI>CA>WMH.
[2010-9] Kakehi, J.-I. et al., FEBS Lett. 584, 3042-3046 (2010)
Thermospermine is a structural isomer of spermine and is required for stem elongation in Arabidopsis thaliana. We noted the C3C3 arrangement of carbon chains in thermospermine (C3C3C4),
which is not present in spermine (C3C4C3), and examined if it is functionally
replaced with norspermine (C3C3C3) or not. Exogenous application of norspermine
to acl5, a mutant defective in the synthesis of thermospermine, partially suppressed
its dwarf phenotype, and down-regulated the level of the acl5 transcript which is much higher than that of the ACL5 transcript in the wild type. Furthermore, in the Zinnia culture, differentiation of mesophyll cells into tracheary elements was
blocked by thermospermine and norspermine but not by spermine. Our results
indicate that norspermine can functionally substitute for thermospermine.
[2010-10] Terui, Y. et al., J. Biol. Chem. 285, 28698-28707 (2010)
We searched for proteins whose synthesis is enhanced by polyamines at the
stationary phase of cell growth using an Escherichia coli polyamine-requiring mutant in which cell viability is greatly decreased
by polyamine deficiency. The synthesis of ribosome modulation factor (RMF)
was strongly enhanced by polyamines at the level of translation at the
stationary phase of cell growth. In rmf mRNA, a Shine-Dalgarno (SD) sequence is located 11 nucleotides upstream of the initiation codon AUG. When the SD sequence was moved to the more common position 8 nucleotides upstream of the initiation codon, the degree of polyamine stimulation was reduced, although the level of RMF synthesis was markedly increased. Polyamine stimulation of RMF synthesis was found to be caused by a selective structural change of the bulged-out region of the initiation site of rmf mRNA. The decrease in cell viability caused by polyamine deficiency was prevented by the addition of a modified rmf gene whose synthesis is not influenced by polyamines. The results indicate
that polyamines enhance cell viability of E. coli at least in part by enhancing RMF synthesis.
[2010-11] Higashi, K. et al., J. Biol. Chem. 285, 39061-39069 (2010)
Amino acid residues on PotB and PotC involved in spermidine uptake were
identified by random and site-directed mutagenesis. It was found that Trp8,
Tyr43, Trp100, Leu110, and Tyr261 in PotB and Trp46, Asp108,
Glu169, Ser196, Asp198, and Asp199 in PotC were strongly involved
in spermidine uptake and that Tyr160, Glu172, and Leu274 in PotB
and Tyr19, Tyr88, Tyr148, Glu160, Leu195, and Tyr211 in PotC
were moderately involved in spermidine uptake. Among 11 amino acid residues
that were strongly involved in spermidine uptake, Trp8 in PotB was important
for insertion of PotB and PotC into membranes. Tyr43, Trp100, and Leu110
in PotB and Trp46, Asp108, Ser196, and Asp198 in PotC were found
to be involved in the interaction with PotD. Leu110 and Tyr261 in PotB
and Asp108, Asp198, and Asp199 in PotC were involved in the recognition
of spermidine, and Trp100 and Tyr261 in PotB and Asp108, Glu169,
and Asp198 in PotC were involved in ATPase activity of PotA. Accordingly,
Trp100 in PotB was involved in both PotD recognition and ATPase activity,
Leu110 in PotB was involved in both PotD and spermidine recognition,
and Tyr261 in PotB was involved in both spermidine recognition and ATPase
activity. Asp108 and Asp198 in PotC were involved in PotD and spermidine
recognition as well as ATPase activity. These results suggest that spermidine
passage from PotD to the cytoplasm is coupled to the ATPase activity of
PotA through a structural change of PotA by its ATPase activity.
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