The N- and C-terminal fragments of ubiquitin are important for the antimicrobial activities.
Secretory granules of chromaffin cells contain catecholamines and several antimicrobial peptides derived from chromogranins and proenkephalin-A. These peptides are secreted in the extracellular medium following exocytosis. Here, we show that ubiquitin is stored in secretory chromaffin granules and released into the circulation upon stimulation of chromaffin cells. We also show that the C-terminal fragment (residues 65-76) of ubiquitin displays, at the micromolar range, a lytic antifungal activity. Using confocal laser scan microscopy and rhodamine-labeled synthetic peptides, we could demonstrate that the C-terminal peptide (residues 65-76) is able to cross the cell wall and the plasma membrane of fungi and to accumulate in fungi, whereas the N-terminal peptide (residues 1-34) is stopped at the fungal wall level. Furthermore, these two peptides act synergistically to kill filamentous fungi. Because of the interaction of the C-terminal sequence of ubiquitin with calmodulin, the synthetic peptide (residues 65-76) was tested in vitro against calmodulin-dependent calcineurin, an enzyme crucial for fungal growth. This peptide was found to inhibit the phosphatase activity of calcineurin. Our data show a new property of ubiquitin C-terminal-derived peptide (65-76) that could be used with N-terminal peptide (1-34) as a new potent antifungal agent.
Kieffer
Anne-Estelle
AE
INSERM Unité 575, IFR 37, Physiopathologie du Système Nerveux, Strasbourg, France.
Goumon
Yannick
Y
Ruh
Olivier
O
Chasserot-Golaz
Sylvette
S
Nullans
Gérard
G
Gasnier
Claire
C
Aunis
Dominique
D
Metz-Boutigue
Marie-Héléne
MH
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001232:Aspergillus fumigatus / Q000187:drug effects; D001410:Bacillus megaterium / Q000187:drug effects; D019703:Calcineurin / Q000378:metabolism; D065095:Calcineurin Inhibitors; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D019439:Chromaffin Cells / Q000737:chemistry / Q000378:metabolism; D004357:Drug Synergism; D008826:Microbial Sensitivity Tests; D016982:Micrococcus luteus / Q000187:drug effects; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000187:drug effects; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology*; D025801:Ubiquitin / Q000737:chemistry / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D065095:Calcineurin Inhibitors; D010446:Peptide Fragments; D025801:Ubiquitin; D019703:Calcineurin