Phosphorylation of vanilloid receptor 1 by Ca2+/calmodulin-dependent kinase II regulates its vanilloid binding.
Vanilloid receptor 1 (VR1), a capsaicin receptor, is known to play a major role in mediating inflammatory thermal nociception. Although the physiological role and biophysical properties of VR1 are known, the mechanism of its activation by ligands is poorly understood. Here we show that VR1 must be phosphorylated by Ca2+-calmodulin dependent kinase II (CaMKII) before its activation by capsaicin. In contrast, the dephosphorylation of VR1 by calcineurin leads to a desensitization of the receptor. Moreover, point mutations in VR1 at two putative consensus sites for CaMKII failed to elicit capsaicin-sensitive currents and caused a concomitant reduction in VR1 phosphorylation in vivo. Such mutants also lost their high affinity binding with [3H]resiniferatoxin, a potent capsaicin receptor agonist. We conclude that the dynamic balance between the phosphorylation and dephosphorylation of the VR1 channel by CaMKII and calcineurin, respectively, controls the activation/desensitization states by regulating VR1 binding. Furthermore, because sensitization by protein kinase A and C converge at these sites, phosphorylation stress in the cell appears to control a wide range of excitabilities in response to various adverse stimuli.
Jung
Jooyoung
J
Sensory Research Center, Creative Research Initiatives, Seoul National University, College of Pharmacy, Kwanak-Gu, Shinlim 9-dong, Seoul 151-742, Korea.
Shin
Jae Soo
JS
Lee
Soon-Youl
SY
Hwang
Sun Wook
SW
Koo
Jaeyeon
J
Cho
Hawon
H
Oh
Uhtaek
U
D000818:Animals; D001665:Binding Sites; D019921:Biotinylation; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D002211:Capsaicin / Q000737:chemistry; D002460:Cell Line; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004224:Diterpenes / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D007700:Kinetics; D008024:Ligands; D008954:Models, Biological; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D011955:Receptors, Drug / Q000378:metabolism*
D004224:Diterpenes; D008024:Ligands; D011955:Receptors, Drug; C024353:resiniferatoxin; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002211:Capsaicin