Document Detail


N-glycosylation determines ionic permeability and desensitization of the TRPV1 capsaicin receptor.
MedLine Citation:
PMID:  22570472     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The balance of glycosylation and deglycosylation of ion channels can markedly influence their function and regulation. However, the functional importance of glycosylation of the TRPV1 receptor, a key sensor of pain-sensing nerves, is not well understood, and whether TRPV1 is glycosylated in neurons is unclear. We report that TRPV1 is N-glycosylated and that N-glycosylation is a major determinant of capsaicin-evoked desensitization and ionic permeability. Both N-glycosylated and unglycosylated TRPV1 was detected in extracts of peripheral sensory nerves by Western blotting. TRPV1 expressed in HEK-293 cells exhibited various degrees of glycosylation. A mutant of asparagine 604 (N604T) was not glycosylated but did not alter plasma membrane expression of TRPV1. Capsaicin-evoked increases in intracellular calcium ([Ca(2+)](i)) were sustained in wild-type TRPV1 HEK-293 cells but were rapidly desensitized in N604T TRPV1 cells. There was marked cell-to-cell variability in capsaicin responses and desensitization between individual cells expressing wild-type TRPV1 but highly uniform responses in cells expressing N604T TRPV1, consistent with variable levels of glycosylation of the wild-type channel. These differences were also apparent when wild-type or N604T TRPV1-GFP fusion proteins were expressed in neurons from trpv1(-/-) mice. Capsaicin evoked a marked, concentration-dependent increase in uptake of the large cationic dye YO-PRO-1 in cells expressing wild-type TRPV1, indicative of loss of ion selectivity, that was completely absent in cells expressing N604T TRPV1. Thus, TRPV1 is variably N-glycosylated and glycosylation is a key determinant of capsaicin regulation of TRPV1 desensitization and permeability. Our findings suggest that physiological or pathological alterations in TRPV1 glycosylation would affect TRPV1 function and pain transmission.
Authors:
Nicholas A Veldhuis; Michael J Lew; Fe C Abogadie; Daniel P Poole; Ernest A Jennings; Jason J Ivanusic; Helge Eilers; Nigel W Bunnett; Peter McIntyre
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-05-08
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  287     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-06-25     Completed Date:  2012-09-20     Revised Date:  2013-06-25    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  21765-72     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, University of Melbourne, Parkville, Victoria, 3010, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Biotinylation
Cell Membrane / metabolism
Coloring Agents / pharmacology
Dose-Response Relationship, Drug
Genetic Vectors
Glycosylation
HEK293 Cells
Humans
Ions
Male
Mice
Mice, Transgenic
Neurons / metabolism
Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / chemistry
Permeability
Protein Binding
Protein Structure, Tertiary
Rats
TRPV Cation Channels / chemistry*,  metabolism
Grant Support
ID/Acronym/Agency:
DK39957/DK/NIDDK NIH HHS; DK43207/DK/NIDDK NIH HHS; DK57840/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Coloring Agents; 0/Ions; 0/TRPV Cation Channels; 0/TRPV1 receptor; EC 3.5.1.52/Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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