title: Calcium/calmodulin-dependent serine protein kinase (CASK) is a new intracellular modulator of P2X3 receptors.
abstract: ATP-gated P2X3 receptors of sensory ganglion neurons are important transducers of painful stimuli and are modulated by extracellular algogenic substances, via changes in the receptor phosphorylation state. The present study investigated the role of calcium/calmodulin-dependent serine protein kinase (CASK) in interacting and controlling P2X3 receptor expression and function in mouse trigeminal ganglia. Most ganglion neurons in situ or in culture co-expressed P2X3 and CASK. CASK was immunoprecipitated with P2X3 receptors from trigeminal ganglia and from P2X3/CASK-cotransfected human embryonic kidney (HEK) cells. Recombinant P2X3/CASK expression in HEK cells increased serine phosphorylation of P2X3 receptors, typically associated with receptor upregulation. CASK deletion mutants also enhanced P2X3 subunit expression. After silencing CASK, cell surface P2X3 receptor expression was decreased, which is consistent with depressed P2X3 currents. The reduction in P2X3 expression levels was reversed by the proteasomal inhibitor MG-132. Moreover, neuronal CASK/P2X3 interaction was up-regulated by nerve growth factor (NGF) signaling and down-regulated by P2X3 agonist-induced desensitization. These data suggest a novel interaction between CASK and P2X3 receptors with positive outcome for receptor stability and function. As CASK-mediated control of P2X3 receptors was dependent on the receptor activation state, CASK represents an intracellular gateway to regulate purinergic nociceptive signaling.
authors.affiliation: Neuroscience Department, International School for Advanced Studies-SISSA, Trieste, Italy.
authors.forename: Aswini
authors.initials: A
authors.lastname: Gnanasekaran
authors.forename: Mayya
authors.initials: M
authors.lastname: Sundukova
authors.forename: Swathi
authors.initials: S
authors.lastname: Hullugundi
authors.forename: Nicol
authors.initials: N
authors.lastname: Birsa
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bianchini
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Hsueh
authors.forename: Andrea
authors.initials: A
authors.lastname: Nistri
authors.forename: Elsa
authors.initials: E
authors.lastname: Fabbretti
mesh_terms: D019921:Biotinylation; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D017950:Ganglia, Sensory / Q000166:cytology / Q000378:metabolism; D020868:Gene Silencing; D051528:Guanylate Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D047468:Immunoprecipitation; D007976:Leupeptins / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D058477:Receptors, Purinergic P2X3 / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism
chemical_list: D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D058477:Receptors, Purinergic P2X3; C106868:CASK kinases; D051528:Guanylate Kinases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde