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Structural basis for interspecies differences in the TRPA1 receptor activation
Synytsya, Viktor ; Šulc, Miroslav (advisor) ; Hudeček, Jiří (referee)
Ankyrin transient receptor potential channel TRPA1 is an excitatory ion channel that transduces nociceptive information on primary aferent sensory nerves of mammals and other organisms. Structure function studies on TRPA1 are valuable for understanding the mechanisms of channel activation and for specific drug discovery efforts, however, significant interspecies differences hamper direct transfer of findings in animals to human. On the other hand, the interspecies differences may prompt identification of many important functional domains. The aim of this bachelor thesis is to give an overview of recent evidence regarding the functional and structural properties of human TRPA1 ion channels from the point of view of the comparison of the most important interspecies differences among TRPA1 orthologs. The experimental part is focused on the comparison of activation properties of human TRPA1 channel with a chimera in which the fifth transmembrane region was replaced by that from Drosophila melanogaster. The presented results obtained by electrophysiological technique patch-clamp demonstrate that outward membrane currents induced by depolarizing voltage are significantly reduced in chimera, which indicates an important role of the fifth transmembrane domain in TRPA1 channel gating (In Czech). Key words:...
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Role of reactive cysteines in the activation of the human TRPA1 ion channel
Synytsya, Viktor ; Vlachová, Viktorie (advisor) ; Zemková, Hana (referee)
TRPA1 is a thermosensitive ion channel from the family of TRP (transient receptor potential) receptors. In primary sensory neurons, TRPA1 is an important transducer of painful stimuli, where it contributes to detection of noxious, irritant and inflammatory compounds of endogenous and exogenous origin. The major activation mode of TRPA1 is covalent modification of N-terminal cysteines or lysines by electrophilic compounds. The potency of the electrophilic agonists is increased by voltage dependency of the TRPA1 channel, which contributes substantially during membrane depolarization. To date, the role of several cysteine residues in the N- terminus has been demonstrated. However, the functional role of six cysteines in the transmembrane domain is still unknown. The first part of the thesis focuses on the functional role of the transmembrane cysteines in the activation of human TRPA1 channel. Our results indicate that these sites do not mediate reactive-electrophile-induced activation but four of the six cysteines substantially contribute to voltage-dependent gating of the channel and two participate in calcium-dependent modulation of TRPA1. In the second part of this thesis we aim to explore the proximity of two specific charged residues, located in the linker between the fourth and the fifth...
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Structural basis for interspecies differences in the TRPA1 receptor activation
Synytsya, Viktor ; Šulc, Miroslav (advisor) ; Hudeček, Jiří (referee)
Ankyrin transient receptor potential channel TRPA1 is an excitatory ion channel that transduces nociceptive information on primary aferent sensory nerves of mammals and other organisms. Structure function studies on TRPA1 are valuable for understanding the mechanisms of channel activation and for specific drug discovery efforts, however, significant interspecies differences hamper direct transfer of findings in animals to human. On the other hand, the interspecies differences may prompt identification of many important functional domains. The aim of this bachelor thesis is to give an overview of recent evidence regarding the functional and structural properties of human TRPA1 ion channels from the point of view of the comparison of the most important interspecies differences among TRPA1 orthologs. The experimental part is focused on the comparison of activation properties of human TRPA1 channel with a chimera in which the fifth transmembrane region was replaced by that from Drosophila melanogaster. The presented results obtained by electrophysiological technique patch-clamp demonstrate that outward membrane currents induced by depolarizing voltage are significantly reduced in chimera, which indicates an important role of the fifth transmembrane domain in TRPA1 channel gating (In Czech). Key words:...
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