title: AKAP150-mediated TRPV1 sensitization is disrupted by calcium/calmodulin.
abstract: BACKGROUND
  The transient receptor potential vanilloid type1 (TRPV1) is expressed in nociceptive sensory neurons and is sensitive to phosphorylation. A-Kinase Anchoring Protein 79/150 (AKAP150) mediates phosphorylation of TRPV1 by Protein Kinases A and C, modulating channel activity. However, few studies have focused on the regulatory mechanisms that control AKAP150 association with TRPV1. In the present study, we identify a role for calcium/calmodulin in controlling AKAP150 association with, and sensitization of, TRPV1.
  
  
  RESULTS
  In trigeminal neurons, intracellular accumulation of calcium reduced AKAP150 association with TRPV1 in a manner sensitive to calmodulin antagonism. This was also observed in transfected Chinese hamster ovary (CHO) cells, providing a model for conducting molecular analysis of the association. In CHO cells, the deletion of the C-terminal calmodulin-binding site of TRPV1 resulted in greater association with AKAP150, and increased channel activity. Furthermore, the co-expression of wild-type calmodulin in CHOs significantly reduced TRPV1 association with AKAP150, as evidenced by total internal reflective fluorescence-fluorescence resonance energy transfer (TIRF-FRET) analysis and electrophysiology. Finally, dominant-negative calmodulin co-expression increased TRPV1 association with AKAP150 and increased basal and PKA-sensitized channel activity.
  
  
  CONCLUSIONS
  the results from these studies indicate that calcium/calmodulin interferes with the association of AKAP150 with TRPV1, potentially extending resensitization of the channel.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: Sraboni
authors.initials: S
authors.lastname: Chaudhury
authors.forename: Manjot
authors.initials: M
authors.lastname: Bal
authors.forename: Sergei
authors.initials: S
authors.lastname: Belugin
authors.forename: Mark S
authors.initials: MS
authors.lastname: Shapiro
authors.forename: Nathaniel A
authors.initials: NA
authors.lastname: Jeske
mesh_terms: D054758:A Kinase Anchor Proteins / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D031541:Fluorescence Resonance Energy Transfer; D042541:Intracellular Space / Q000378:metabolism; D008297:Male; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D017384:Sequence Deletion; D050916:TRPV Cation Channels / Q000378:metabolism*
chemical_list: D054758:A Kinase Anchor Proteins; C415703:Akap5 protein, rat; D002147:Calmodulin; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; D002118:Calcium