Sandbox Reserved 1652: Difference between revisions
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=== Regulation === | === Regulation === | ||
====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>G. Smutzer et R. K. Devassy, « Integrating TRPV1 Receptor Function with Capsaicin Psychophysics », Advances in Pharmacological Sciences, janv. 14, 2016.</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>G. Smutzer et R. K. Devassy, « Integrating TRPV1 Receptor Function with Capsaicin Psychophysics », Advances in Pharmacological Sciences, janv. 14, 2016.</ref> | ||
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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 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 the same quantity of agonist leads to a better openings of ion channels. | ||
====Desensitization==== | |||
A repeated exposure of TRPV1 to capsaicin fails to activate the receptor. It occurs by a CA2+-dependent mechanism that leads to a '''desphosphorylation''' by the '''calcineurin''' [https://en.wikipedia.org/wiki/Phosphatase phosphatase] of the serine and threonine residues which have been previously phosphorylated by PKA. Thus, the decrease in TRPV1 phosphorylation diminish the sensitivity of the capsaicin channel and leads to a decrease in capsaicin's response by '''negative feedback'''. | A repeated exposure of TRPV1 to capsaicin fails to activate the receptor. It occurs by a CA2+-dependent mechanism that leads to a '''desphosphorylation''' by the '''calcineurin''' [https://en.wikipedia.org/wiki/Phosphatase phosphatase] of the serine and threonine residues which have been previously phosphorylated by PKA. Thus, the decrease in TRPV1 phosphorylation diminish the sensitivity of the capsaicin channel and leads to a decrease in capsaicin's response by '''negative feedback'''. | ||
