Sandbox Reserved 1652: Difference between revisions
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Bound [https://en.wikipedia.org/wiki/Capsaicin capsaicin] is oriented in a « tail-up, head down » configuration. In this configuration the vanillyl and amide groups of capsaicin form specific interactions with TRPV1,capsaicin is anchored into the receptor.<ref>F. Yang et al., « Structural mechanism underlying capsaicin binding and activation of the TRPV1 ion channel », Nat. Chem. Biol., vol. 11, no 7, Art. no 7, juill. 2015, doi: 10.1038/nchembio.1835.</ref> | Bound [https://en.wikipedia.org/wiki/Capsaicin capsaicin] is oriented in a « tail-up, head down » configuration. In this configuration the vanillyl and amide groups of capsaicin form specific interactions with TRPV1,capsaicin is anchored into the receptor.<ref>F. Yang et al., « Structural mechanism underlying capsaicin binding and activation of the TRPV1 ion channel », Nat. Chem. Biol., vol. 11, no 7, Art. no 7, juill. 2015, doi: 10.1038/nchembio.1835.</ref> | ||
The capsaicin cycle binds via hydrogen bounds to amino acids on the S3 helix (Y511, S513), on the S4-S5 linker (E571) and on the S6 helix (T671). The amid group of capsaicin binds the S4 helix (T551).<ref | The capsaicin cycle binds via hydrogen bounds to amino acids on the S3 helix (Y511, S513), on the S4-S5 linker (E571) and on the S6 helix (T671). The amid group of capsaicin binds the S4 helix (T551).<ref name="Integrating TRPV1 Receptor Function with Capsaicin Psychophysics"> | ||
Capsaicin maintains TRPV1 in an open state by «pull and contact» interactions. A conformational change wave spread over the whole pore.<ref>F. Yang et al., « The conformational wave in capsaicin activation of transient receptor potential vanilloid 1 ion channel », Nat. Commun., vol. 9, no 1, Art. no 1, juill. 2018, doi: 10.1038/s41467-018-05339-6.</ref>. This leads to the massive enter of Ca2+ and Na+ in the cytoplasm of the nerve fiber and to the depolarization of the nerve fiber. When depolarization reach a theshold value it triggers the generation of an [https://en.wikipedia.org/wiki/Action_potential action potential] causing a painful sensation.<ref name="TRPV1"/> | Capsaicin maintains TRPV1 in an open state by «pull and contact» interactions. A conformational change wave spread over the whole pore.<ref>F. Yang et al., « The conformational wave in capsaicin activation of transient receptor potential vanilloid 1 ion channel », Nat. Commun., vol. 9, no 1, Art. no 1, juill. 2018, doi: 10.1038/s41467-018-05339-6.</ref>. This leads to the massive enter of Ca2+ and Na+ in the cytoplasm of the nerve fiber and to the depolarization of the nerve fiber. When depolarization reach a theshold value it triggers the generation of an [https://en.wikipedia.org/wiki/Action_potential action potential] causing a painful sensation.<ref name="TRPV1"/> | ||
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====Sensitization==== | ====Sensitization==== | ||
'''Phosphorylation''' of the TRPV1 receptor leads to its sensitization.Phosphorylations occurs on multiple phosphorylation sites at both N-terminal and C-terminal sites of TRPV1 by [https://en.wikipedia.org/wiki/Kinase kinases]. Phosphorylations are either caused by '''PKC''' (IP3 signalling), by '''PKA''' (AMPc signalling) or by '''CamKII'''.<ref>K. W. Ho, N. J. Ward, et D. J. Calkins, « TRPV1: a stress response protein in the central nervous system », Am. J. Neurodegener. Dis., vol. 1, no 1, p. 1‑14, avr. 2012.</ref><ref | '''Phosphorylation''' of the TRPV1 receptor leads to its sensitization.Phosphorylations occurs on multiple phosphorylation sites at both N-terminal and C-terminal sites of TRPV1 by [https://en.wikipedia.org/wiki/Kinase kinases]. Phosphorylations are either caused by '''PKC''' (IP3 signalling), by '''PKA''' (AMPc signalling) or by '''CamKII'''.<ref>K. W. Ho, N. J. Ward, et D. J. Calkins, « TRPV1: a stress response protein in the central nervous system », Am. J. Neurodegener. Dis., vol. 1, no 1, p. 1‑14, avr. 2012.</ref><ref name="Integrating TRPV1 Receptor Function with Capsaicin Psychophysics"> | ||
PKC phosphorlyates TRPV1 at S800,S502, PKA phosphorylates TRPV1 at S116. The phosphorylation of TRPV1 lead to an increase in the expression of TRPV1 at the membrane surface.<ref>K. W. Ho, N. J. Ward, et D. J. Calkins, « TRPV1: a stress response protein in the central nervous system », Am. J. Neurodegener. Dis., vol. 1, no 1, p. 1‑14, avr. 2012.</ref>. Moreover, phosphorylated TRPV1 would have a reduced channel opening threshold.<ref>G. Bhave et al., « Protein kinase C phosphorylation sensitizes but does not activate the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) », Proc. Natl. Acad. Sci., vol. 100, no 21, p. 12480‑12485, oct. 2003, doi: 10.1073/pnas.2032100100.</ref>. As a result phosphorylated TRPV1 are more responsive to agonist because they are '''overexpressed''' and because the same quantity of agonist leads to a better openings of ion channels. | PKC phosphorlyates TRPV1 at S800,S502, PKA phosphorylates TRPV1 at S116. The phosphorylation of TRPV1 lead to an increase in the expression of TRPV1 at the membrane surface.<ref>K. W. Ho, N. J. Ward, et D. J. Calkins, « TRPV1: a stress response protein in the central nervous system », Am. J. Neurodegener. Dis., vol. 1, no 1, p. 1‑14, avr. 2012.</ref>. Moreover, phosphorylated TRPV1 would have a reduced channel opening threshold.<ref>G. Bhave et al., « Protein kinase C phosphorylation sensitizes but does not activate the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) », Proc. Natl. Acad. Sci., vol. 100, no 21, p. 12480‑12485, oct. 2003, doi: 10.1073/pnas.2032100100.</ref>. As a result phosphorylated TRPV1 are more responsive to agonist because they are '''overexpressed''' and because the same quantity of agonist leads to a better openings of ion channels. | ||
