Search

Regulatory features of protein-induced membrane fusion are largely unclear, particularly at the level of the fusion peptide. Fusion peptides being part of larger protein complexes, such investigations are met with technical limitations. Here, we show that the fusion activity of influenza virus or Golgi membranes is strongly inhibited by minor amounts of (lyso)lipids when present in the target membrane but not when inserted into the viral or Golgi membrane itself. To investigate the underlying mechanism, we employ a membrane-anchored peptide system and show that fusion is similarly regulated by these lipids when inserted into the target but not when present in the peptide-containing membrane. Peptide-induced fusion is regulated by a reversible switch of secondary structure from a fusion-permissive alpha-helix to a nonfusogenic beta-sheet. The "on/off" activation of this switch is governed by minor amounts of (lyso)-phospholipids in targets, causing a drop in alpha-helix and a dramatic increase in beta-sheet contents. Concomitantly, fusion is inhibited, due to impaired peptide insertion into the target membrane. Our observations in biological fusion systems together with the model studies suggest that distinct lipids in target membranes provide a means for regulating membrane fusion by causing a reversible secondary structure switch of the fusion peptides., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Regulatory features of protein-induced membrane fusion are largely unclear, particularly at the level of the fusion peptide. Fusion peptides being part of larger protein complexes, such investigations are met with technical limitations. Here, we show that the fusion activity of influenza virus or Golgi membranes is strongly inhibited by minor amounts of (lyso)lipids when present in the target membrane but not when inserted into the viral or Golgi membrane itself. To investigate the underlying mechanism, we employ a membrane-anchored peptide system and show that fusion is similarly regulated by these lipids when inserted into the target but not when present in the peptide-containing membrane. Peptide-induced fusion is regulated by a reversible switch of secondary structure from a fusion-permissive alpha-helix to a nonfusogenic beta-sheet. The "on/off" activation of this switch is governed by minor amounts of (lyso)-phospholipids in targets, causing a drop in alpha-helix and a dramatic increase in beta-sheet contents. Concomitantly, fusion is inhibited, due to impaired peptide insertion into the target membrane. Our observations in biological fusion systems together with the model studies suggest that distinct lipids in target membranes provide a means for regulating membrane fusion by causing a reversible secondary structure switch of the fusion peptides., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

We recently demonstrated that an amphipathic net-negatively charged peptide consisting of 11 amino acids (WAE 11) strongly promotes fusion of large unilamellar liposomes (LUV) when anchored to a liposomal membrane [Pecheur, E. I. Hoekstra, D. Sainte-Marie, J. Maurin, L. Bienvenue, A. and Philippot, J. R. (1997) Biochemistry 36, 3773-3781]. To elucidate a potential relationship between peptide structure and its fusogenic properties and to test the hypothesis that specific structural motifs are a prerequisite for WAE-induced fusion, three 11-mer WAE-peptide analogues (WAK, WAEPro, and WAS) were synthesized and investigated for their structure and fusion activity. Structural analysis of the synthetic peptides by infrared attenuated total reflection spectroscopy reveals a distinct propensity of each peptide toward a helical structure after their anchorage to a liposomal surface, emphasizing the importance of anchorage on conveying a secondary structure, thereby conferring fusogenicity to these peptides. However, whereas WAE and WAK peptides displayed an essentially nonleaky fusion process, WAS- and WAEPro-induced fusion was accompanied by substantial leakage. It appears that peptide helicity as such is not a sufficient condition to convey optimal fusion properties to these 11-mer peptides. Studies of changes in the intrinsic Trp fluorescence and iodide quenching experiments were carried out and revealed the absence of migration of the Trp residue of WAS and WAEPro to a hydrophobic environment, upon their interaction with the target membranes. These results do not support the penetration of both peptides as their mode of membrane interaction and destabilization but rather suggest their folding along the vesicle surface, posing them as surface-seeking helixes. This is in striking contrast to the behavior observed for WAE and WAK, for which at least partial penetration of the Trp residue was demonstrated. These results indicate that subtle differences in the primary sequen, In Vitro, Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

We recently demonstrated that an amphipathic net-negatively charged peptide consisting of 11 amino acids (WAE 11) strongly promotes fusion of large unilamellar liposomes (LUV) when anchored to a liposomal membrane [Pecheur, E. I. Hoekstra, D. Sainte-Marie, J. Maurin, L. Bienvenue, A. and Philippot, J. R. (1997) Biochemistry 36, 3773-3781]. To elucidate a potential relationship between peptide structure and its fusogenic properties and to test the hypothesis that specific structural motifs are a prerequisite for WAE-induced fusion, three 11-mer WAE-peptide analogues (WAK, WAEPro, and WAS) were synthesized and investigated for their structure and fusion activity. Structural analysis of the synthetic peptides by infrared attenuated total reflection spectroscopy reveals a distinct propensity of each peptide toward a helical structure after their anchorage to a liposomal surface, emphasizing the importance of anchorage on conveying a secondary structure, thereby conferring fusogenicity to these peptides. However, whereas WAE and WAK peptides displayed an essentially nonleaky fusion process, WAS- and WAEPro-induced fusion was accompanied by substantial leakage. It appears that peptide helicity as such is not a sufficient condition to convey optimal fusion properties to these 11-mer peptides. Studies of changes in the intrinsic Trp fluorescence and iodide quenching experiments were carried out and revealed the absence of migration of the Trp residue of WAS and WAEPro to a hydrophobic environment, upon their interaction with the target membranes. These results do not support the penetration of both peptides as their mode of membrane interaction and destabilization but rather suggest their folding along the vesicle surface, posing them as surface-seeking helixes. This is in striking contrast to the behavior observed for WAE and WAK, for which at least partial penetration of the Trp residue was demonstrated. These results indicate that subtle differences in the primary sequen, In Vitro, Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Appartient à l’ensemble documentaire : EnPC000, Appartient à l’ensemble documentaire : EnPCcorp02, Appartient à l’ensemble documentaire : EnPCcorp13, Appartient à l’ensemble documentaire : EnPCthèm06, Avec mode texte

Avec mode texte

Avec mode texte