| 1. |
- Giacomelli, C., et al.
(författare)
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Copper (II) ions modulate Angiogenin activity in human endothelial cells
- 2015
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Ingår i: International Journal of Biochemistry & Cell Biology. - : Elsevier BV. - 1357-2725. ; 60, s. 185-196
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenin (ANG), a member of the secreted ribonuclease family, is a potent angiogenesis stimulator that interacts with endothelial cells inducing a wide range of responses. Metal ions dyshomeostasis play a fundamental role in the onset of neurodegenerative diseases, in particular copper that is also involved in angiogenesis processes. It is known that vascular pathologies are present in neurodegenerative diseases and Angiogenin is down-regulated in Alzheimer and Parkinson diseases, as well as it has been found as one of the mutated genes in amyotrophic lateral sclerosis (ALS). Copper (II) induces an increase of Angiogenin binding to endothelial cells but, so far, the relationship between copper-ANG and angiogenesis induction remain unclear. Herein, the effects of copper (II) ions on Angiogenin activity and expression were evaluated. The binding of copper was demonstrated to affect the intracellular localization of the protein decreasing its nuclear translocation. Moreover, the ANG-copper (II) system negatively affects the protein-induced angiogenesis, as well as endothelial cells migration. Surprisingly, copper also reveals the ability to modulate the Angiogenin transcription. These results highlight the tight relationship between copper and Angiogenin, pointing out the biological relevance of ANG-copper system in the regulation of endothelial cell function, and revealing a possible new mechanism at the basis of vascular pathologies.
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| 2. |
- La Mendola, D., et al.
(författare)
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Copper binding to naturally occurring, lactam form of angiogenin differs from that to recombinant protein, affecting their activity
- 2016
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Ingår i: Metallomics. - : Oxford University Press (OUP). - 1756-5901 .- 1756-591X. ; 8:1, s. 118-124
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenin is a member of the ribonuclease family and a normal constituent of human plasma. It is one of the most potent angiogenic factors known and is overexpressed in different types of cancers. Copper is also an essential cofactor in angiogenesis and, during this process, it is mobilized from inside to outside of the cell. To date, contrasting results have been reported about copper(II) influencing angiogenin activity. However, in these studies, the recombinant form of the protein was used. Unlike recombinant angiogenin, that contains an extra methionine with a free terminal amino group, the naturally occurring protein present in human plasma starts with a glutamine residue that spontaneously cyclizes to pyroglutamate, a lactam derivative. Herein, we report spectroscopic evidence indicating that copper(II) experiences different coordination environments in the two protein isoforms, and affects their RNase and angiogenic activity differently. These results show how relatively small differences between recombinant and wild type proteins can result in markedly different behaviours.
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| 3. |
- Magrì, A., et al.
(författare)
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Coordination environment of Cu(II) ions bound to N-terminal peptide fragments of angiogenin protein
- 2016
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 17:8
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenin (Ang) is a potent angiogenic factor, strongly overexpressed in patients affected by different types of cancers. The specific Ang cellular receptors have not been identified, but it is known that Ang–actin interaction induces changes both in the cell cytoskeleton and in the extracellular matrix. Most in vitro studies use the recombinant form (r-Ang) instead of the form that is normally present in vivo (“wild-type”, wt-Ang). The first residue of r-Ang is a methionine, with a free amino group, whereas wt-Ang has a glutamic acid, whose amino group spontaneously cyclizes in the pyro-glutamate form. The Ang biological activity is influenced by copper ions. To elucidate the role of such a free amino group on the protein–copper binding, we scrutinized the copper(II) complexes with the peptide fragments Ang(1–17) and AcAng(1–17), which encompass the sequence 1–17 of angiogenin (QDNSRYTHFLTQHYDAK-NH2), with free amino and acetylated N-terminus, respectively. Potentiometric, ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR) and circular dichroism (CD) studies demonstrate that the two peptides show a different metal coordination environment. Confocal microscopy imaging of neuroblastoma cells with the actin staining supports the spectroscopic results, with the finding of different responses in the cytoskeleton organization upon the interaction, in the presence or not of copper ions, with the free amino and the acetylated N-terminus peptides. © 2016 by the authors; licensee MDPI, Basel, Switzerland.
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