2pnn
From Proteopedia
Crystal Structure of the Ankyrin Repeat Domain of Trpv1
Structural highlights
FunctionTRPV1_RAT Receptor-activated non-selective calcium permeant cation channel involved in detection of noxious chemical and thermal stimuli. Seems to mediate proton influx and may be involved in intracellular acidosis in nociceptive neurons. May be involved in mediation of inflammatory pain and hyperalgesia. Sensitized by a phosphatidylinositol second messenger system activated by receptor tyrosine kinases, which involves PKC isozymes and PCL. Activation by vanilloids, like capsaicin, and temperatures higher than 42 degrees Celsius, exhibits a time- and Ca(2+)-dependent outward rectification, followed by a long-lasting refractory state. Mild extracellular acidic pH (6.5) potentiates channel activation by noxious heat and vanilloids, whereas acidic conditions (pH <6) directly activate the channel. Can be activated by endogenous compounds, including 12-hydroperoxytetraenoic acid and bradykinin. Acts as ionotropic endocannabinoid receptor with central neuromodulatory effects. Triggers a form of long-term depression (TRPV1-LTD) mediated by the endocannabinoid anandamine in the hippocampus and nucleus accumbens by affecting AMPA receptors endocytosis.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTRPV1 plays a key role in nociception, as it is activated by heat, low pH, and ligands such as capsaicin, leading to a burning pain sensation. We describe the structure of the cytosolic ankyrin repeat domain (ARD) of TRPV1 and identify a multiligand-binding site important in regulating channel sensitivity within the TRPV1-ARD. The structure reveals a binding site that accommodates triphosphate nucleotides such as ATP, and biochemical studies demonstrate that calmodulin binds the same site. Electrophysiology experiments show that either ATP or PIP2 prevent desensitization to repeated applications of capsaicin, i.e., tachyphylaxis, while calmodulin plays an opposing role and is necessary for tachyphylaxis. Mutations in the TRPV1-ARD binding site eliminate tachyphylaxis. We present a model for the calcium-dependent regulation of TRPV1 via competitive interactions of ATP and calmodulin at the TRPV1-ARD-binding site and discuss its relationship to the C-terminal region previously implicated in interactions with PIP2 and calmodulin. The ankyrin repeats of TRPV1 bind multiple ligands and modulate channel sensitivity.,Lishko PV, Procko E, Jin X, Phelps CB, Gaudet R Neuron. 2007 Jun 21;54(6):905-18. PMID:17582331[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
|
| |||||||||||||||||||
