bims-polyam Biomed News
on Polyamines
Issue of 2019‒12‒22
four papers selected by
Alexander Ivanov
Engelhardt Institute of Molecular Biology

  1. Biomolecules. 2019 Dec 12. pii: E864. [Epub ahead of print]9(12):
    Hsieh JY, Liu YC, Cheng IT, Lee CJ, Wang YH, Fang YS, Liu YL, Liu GY, Hung HC.
      Antizyme (AZ) is a protein that negatively regulates ornithine decarboxylase (ODC). AZ achieves this inhibition by binding to ODC to produce AZ-ODC heterodimers, abolishing enzyme activity and targeting ODC for degradation by the 26S proteasome. In this study, we focused on the biomolecular interactions between the C-terminal domain of AZ (AZ95-228) and ODC to identify the functional elements of AZ that are essential for binding, inhibiting and degrading ODC, and we also identified the crucial factors governing the differential binding and inhibition ability of AZ isoforms toward ODC. Based on the ODC inhibition and AZ-ODC binding studies, we demonstrated that amino acid residues reside within the α1 helix, β5 and β6 strands, and connecting loop between β6 and α2 (residues 142-178), which is the posterior part of AZ95-228, play crucial roles in ODC binding and inhibition. We also identified the essential elements determining the ODC-degradative activity of AZ; amino acid residues within the anterior part of AZ95-228 (residues 120-145) play crucial roles in AZ-mediated ODC degradation. Finally, we identified the crucial factors that govern the differential binding and inhibition of AZ isoforms toward ODC. Mutagenesis studies of AZ1 and AZ3 and their binding and inhibition revealed that the divergence of amino acid residues 124, 150, 166, 171, and 179 results in the differential abilities of AZ1 and AZ3 in the binding and inhibition of ODC.
    Keywords:  AZ isoform; binding affinity; protein–protein interaction; ubiquitin-independent degradation
  2. Vaccines (Basel). 2019 Dec 14. pii: E216. [Epub ahead of print]7(4):
    Dai K, Ma X, Yang Z, Chang YF, Cao S, Zhao Q, Huang X, Wu R, Huang Y, Yan Q, Han X, Ma X, Wen X, Wen Y.
      The potD gene, belonging to the well-conserved ABC (ATP-binding cassette) transport system potABCD, encodes the bacterial substrate-binding subunit of the polyamine transport system. In this study, we found PotD in Haemophilus (Glaesserella) parasuis could actively stimulate both humoral immune and cellular immune responses and elevate lymphocyte proliferation, thus eliciting a Th1-type immune response in a murine immunity and infection model. Stimulation of Raw 264.7 macrophages with PotD validated that Toll-like receptor 4, rather than 2, participated in the positive transcription and expression of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α using qPCR and ELISA. Blocking signal-regulated JNK-MAPK and RelA(p65) pathways significantly decreased PotD-induced pro-inflammatory cytokine production. Overall, we conclude that vaccination of PotD could induce both humoral and cellular immune responses and provide immunoprotection against H. parasuis challenge. The data also suggest that Glaesserella PotD is a novel pro-inflammatory mediator and induces TLR4-dependent pro-inflammatory activity in Raw 264.7 macrophages through JNK-MAPK and RelA(p65) pathways.
    Keywords:  Haemophilus parasuis; PotD; polyamine; pro-inflammatory cytokines; signal pathway
  3. J Proteome Res. 2019 Dec 20.
    Pratavieira M, da Silva Menegasso AR, Roat T, Malaspina O, Palma MS.
      The proboscis extension response (PER) reflex may be used to condition the pairing of an odor with sucrose, which is applied to the antennae, in experiments to induce learning, where the odor represents a conditioned stimulus, while sucrose represents an unconditioned stimulus. A series of studies have been conducted with honeybees relating learning and memory acquisition / retrieval using the PER as a strategy for accessing their ability to exhibit an unconditioned stimulus; however, the major metabolic processes involved in the PER are not well known. Thus, the aim of this investigation is profiling the metabolome of the honeybee brain involved in the PER. In the present study, a semiquantitative approach of MALDI mass spectral imaging (MSI) was used to profile the most abundant metabolites of the honeybee brain that support the PER. It was reported that execution of the PER requires the metabolic transformations of arginine, ornithine, and lysine as substrates for the production of putrescine, cadaverine, spermine, spermidine, 1,3-diaminopropane, and GABA. Considering the global metabolome of the brain of honeybee workers, the PER requires the consumption of large amounts of cadaverine and 1,3-diaminopropane, in parallel with the biosynthesis of high amounts of spermine, spermidine, and ornithine. To exhibit the PER, the brain of honeybee workers processes the conversion of L-arginine and L-lysine through the polyamine pathway, with different regional metabolomic profiles at the individual neuropil level. Using this metabolic route as a reference, the outcomes of the this study are indicating that the antennal lobes and the calices (medial and lateral) were the most active brain regions for supporting the PER.
  4. Plant Cell Environ. 2019 Dec 18.
    Shen S, Liang XG, Zhang L, Zhao X, Liu YP, Lin S, Gao Z, Wang P, Wang ZM, Zhou SL.
      During maize production, drought throughout the flowering stage usually induces seed abortion and yield losses. The influence of postpollination drought stress on seed abortion and its underlying mechanisms are not well characterized. By intervening in the competition for assimilates between kernel siblings under different degrees of postpollination drought stresses accompanied by synchronous pollination (SP) and incomplete pollination (ICP) approaches, the mechanisms of postpollination abortion were investigated at physiological and molecular levels. Upon SP treatment, up to 15% of the fertilized apical kernels were aborted in the drought-exacerbated competition for assimilates. The aborted kernels exhibited weak sucrose hydrolysis and starch synthesis but promoted the synthesis of trehalose-6-phosphate and ethylene. In ICP where basal pollination was prevented, apical kernel growth was restored with reinstated sucrose metabolism and starch synthesis and promoted sucrose and hexose levels under drought stress. In addition, the equilibrium between ethylene and polyamine in response to the drought and pollination treatments was associated with the abortion process. We conclude that competition for assimilates drives postpollination kernel abortion, whereas differences in sugar metabolism and the equilibrium between ethylene and polyamines may be relevant to the "live or die" choice of kernel siblings during this competition. This article is protected by copyright. All rights reserved.
    Keywords:  abortion; assimilate; ethylene; invertase; kernel set; maize; pollination