tetano
Editor, Senior Moderator
Biochemistry (Mosc). 2018 Aug;83(8):982-991. doi: 10.1134/S0006297918080096.
[h=1]Amphipathic CRAC-Containing Peptides Derived from the Influenza Virus A M1 Protein Modulate Cholesterol-Dependent Activity of Cultured IC-21 Macrophages.[/h] Dunina-Barkovskaya AY[SUP]1[/SUP], Vishnyakova KS[SUP]2[/SUP], Golovko AO[SUP]3[/SUP], Arutyunyan AM[SUP]4[/SUP], Baratova LA[SUP]4[/SUP], Bathishchev OV[SUP]5[/SUP], Radyukhin VA[SUP]6[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Entry of many viral and bacterial pathogens into host cells depends on cholesterol and/or cholesterol-enriched domains (lipid rafts) in the cell membrane. Earlier, we showed that influenza virus A matrix protein M1 contains amphipathic α-helices with exposed cholesterol-recognizing amino acid consensus (CRAC) motifs. In order to test possible functional activity of these motifs, we studied the effects of three synthetic peptides corresponding to the CRAC-containing α-helices of the viral M1 protein on the phagocytic activity of cultured mouse IC-21 macrophages. The following peptides were used: LEVLMEWLKTR (M1 α-helix 3, a.a. 39-49; further referred to as peptide 1), NNMDKAVKLYRKLK (M1 α-helix 6, a.a. 91-105; peptide 2), and GLKNDLLENLQAYQKR (M1 α-helix 13, a.a. 228-243; peptide 3). We found that all three peptides modulated interactions of IC-21 macrophages with non-opsonized 2-?m target particles. The greatest effect was demonstrated by peptide 2: in the presence of 35 μM peptide 2, the phagocytic index of IC-21 macrophages exceeded the control value by 60%; 10-11 mM methyl-β-cyclodextrin abolished this effect. Peptides 1 and 3 exerted weak inhibitory effect in a narrow concentration range of 5-10 μM. The dose-response curves could be approximated by a sum of two (stimulatory and inhibitory) components with different Hill coefficients, suggesting existence of at least two peptide-binding sites with different affinities on the cell surface. CD spectroscopy confirmed that the peptides exhibit structural flexibility in solutions. Altogether, our data indicate that amphipathic CRAC-containing peptides derived from the viral M1 protein modulate lipid raft-dependent processes in IC-21 macrophages.
PMID: 30208834 DOI: 10.1134/S0006297918080096
[h=1]Amphipathic CRAC-Containing Peptides Derived from the Influenza Virus A M1 Protein Modulate Cholesterol-Dependent Activity of Cultured IC-21 Macrophages.[/h] Dunina-Barkovskaya AY[SUP]1[/SUP], Vishnyakova KS[SUP]2[/SUP], Golovko AO[SUP]3[/SUP], Arutyunyan AM[SUP]4[/SUP], Baratova LA[SUP]4[/SUP], Bathishchev OV[SUP]5[/SUP], Radyukhin VA[SUP]6[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Entry of many viral and bacterial pathogens into host cells depends on cholesterol and/or cholesterol-enriched domains (lipid rafts) in the cell membrane. Earlier, we showed that influenza virus A matrix protein M1 contains amphipathic α-helices with exposed cholesterol-recognizing amino acid consensus (CRAC) motifs. In order to test possible functional activity of these motifs, we studied the effects of three synthetic peptides corresponding to the CRAC-containing α-helices of the viral M1 protein on the phagocytic activity of cultured mouse IC-21 macrophages. The following peptides were used: LEVLMEWLKTR (M1 α-helix 3, a.a. 39-49; further referred to as peptide 1), NNMDKAVKLYRKLK (M1 α-helix 6, a.a. 91-105; peptide 2), and GLKNDLLENLQAYQKR (M1 α-helix 13, a.a. 228-243; peptide 3). We found that all three peptides modulated interactions of IC-21 macrophages with non-opsonized 2-?m target particles. The greatest effect was demonstrated by peptide 2: in the presence of 35 μM peptide 2, the phagocytic index of IC-21 macrophages exceeded the control value by 60%; 10-11 mM methyl-β-cyclodextrin abolished this effect. Peptides 1 and 3 exerted weak inhibitory effect in a narrow concentration range of 5-10 μM. The dose-response curves could be approximated by a sum of two (stimulatory and inhibitory) components with different Hill coefficients, suggesting existence of at least two peptide-binding sites with different affinities on the cell surface. CD spectroscopy confirmed that the peptides exhibit structural flexibility in solutions. Altogether, our data indicate that amphipathic CRAC-containing peptides derived from the viral M1 protein modulate lipid raft-dependent processes in IC-21 macrophages.
PMID: 30208834 DOI: 10.1134/S0006297918080096