In a wide range of organisms, from bacteria to humans, numerous proteins have to be posttranslationally acylated to become biologically active. Bacterial repeats in toxin (RTX) cytolysins form a prominent group of proteins that are synthesized as inactive protoxins and undergo posttranslational acylation on ε-amino groups of two internal conserved lysine residues by co-expressed toxin-activating acyltransferases. Here, we investigated how the chemical nature, position, and number of bound acyl chains govern the activities of Bordetella pertussis adenylate cyclase toxin (CyaA), Escherichia coli α-hemolysin (HlyA), and Kingella kingae cytotoxin (RtxA). We found that the three protoxins are acylated in the same E. coli cell background by each of the CyaC, HlyC, and RtxC acyltransferases. We also noted that the acyltransferase selects from the bacterial pool of acyl-acyl carrier proteins (ACPs) an acyl chain of a specific length for covalent linkage to the protoxin. The acyltransferase also selects whether both or only one of two conserved lysine residues of the protoxin will be posttranslationally acylated. Functional assays revealed that RtxA has to be modified by 14-carbon fatty acyl chains to be biologically active, that HlyA remains active also when modified by 16-carbon acyl chains, and that CyaA is activated exclusively by 16-carbon acyl chains. These results suggest that the RTX toxin molecules are structurally adapted to the length of the acyl chains used for modification of their acylated lysine residue in the second, more conserved acylation site.

• MeSH
• Acyltransferases metabolism   MeSH
• Bacteria metabolism   MeSH
• Bacterial Proteins metabolism   MeSH
• Cell Line MeSH
• Hemolysin Proteins metabolism   MeSH
• Fatty Acids metabolism   MeSH
• Mice MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Controlling pain in burn-injured patients poses a major clinical challenge. Recent findings suggest that reducing the activity of the voltage-gated sodium channel Nav1.7 in primary sensory neurons could provide improved pain control in burn-injured patients. Here, we report that partial thickness scalding-type burn injury on the rat paw upregulates Nav1.7 expression in primary sensory neurons 3 h following injury. The injury also induces upregulation in phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB), a marker for nociceptive activation in primary sensory neurons. The upregulation in p-CREB occurs mainly in Nav1.7-immunopositive neurons and exhibits a peak at 5 min and, following a decline at 30 min, a gradual increase from 1 h post-injury. The Nav1.7 blocker protoxin II (ProTxII) or morphine injected intraperitoneally 15 min before or after the injury significantly reduces burn injury-induced spinal upregulation in phosphorylated serine 10 in histone H3 and phosphorylated extracellular signal-regulated kinase 1/2, which are both markers for spinal nociceptive processing. Further, ProTxII significantly reduces the frequency of spontaneous excitatory post-synaptic currents in spinal dorsal horn neurons following burn injury. Together, these findings indicate that using Nav1.7 blockers should be considered to control pain in burn injury. KEY MESSAGES: • Burn injury upregulates Nav1.7 expression in primary sensory neurons. • Burn injury results in increased activity of Nav1.7-expressing primary sensory neurons. • Inhibiting Nav1.7 by protoxin II reduces spinal nociceptive processing. • Nav1.7 represents a potential target to reduce pain in burn injury.

• MeSH
• Analgesics therapeutic use   MeSH
• Voltage-Gated Sodium Channel Blockers therapeutic use   MeSH
• Pain drug therapy   MeSH
• Spinal Cord cytology   physiology   MeSH
• Mice, Inbred C57BL MeSH
• Mice, Knockout MeSH
• NAV1.7 Voltage-Gated Sodium Channel physiology   MeSH
• Sensory Receptor Cells physiology   MeSH
• Spider Venoms therapeutic use   MeSH
• Peptides therapeutic use   MeSH
• Burns drug therapy   MeSH
• Rats, Sprague-Dawley MeSH
• Rats, Wistar MeSH
• Cyclic AMP Response Element-Binding Protein metabolism   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Přírodní toxiny jsou chemické látky biologického původu, produkované jednobuněčnými i mnohobuněčnými organismy ve speciálních žlázách, tkáních a pletivech. Utvářely se v procesu evoluce v mikroorganismech, v houbách, rostlinách i živočiších a v tomto časově dlouhém procesu získaly specifické a mnohdy jedinečné vlastnosti. Jedy některých rostlin nebo i živočichů a jejich toxické vlastnosti byly známy a využívány (popřípadě zneužívány) k různým účelům již v nejstarších úsecích lidských dějin.

• MeSH
• Alkaloids MeSH
• Toxins, Biological MeSH
• Animals, Poisonous MeSH
• Plants, Toxic MeSH
• Poisons MeSH
• Plant Poisoning MeSH
• Toxicology MeSH

• Conspectus
• Farmacie. Farmakologie
• NML Fields
• toxikologie
• biologie