A role of the transient receptor potential domain of vanilloid receptor I in channel gating.
Transient receptor potential vanilloid receptor subtype 1 (TRPV1) is an ionotropic receptor activated by temperature and chemical stimuli. The C-terminal region that is adjacent to the channel gate, recognized as the TRP domain, is a molecular determinant of receptor assembly. However, the role of this intracellular domain in channel function remains elusive. Here, we show that replacement of the TRP domain of TRPV1 with the cognate region of TRPV channels (TRPV2-TRPV6) did not affect receptor assembly and trafficking to the cell surface, although those receptors containing the TRP domain of the distantly related TRPV5 and TRPV6 did not display ion channel activity. Notably, functional chimeras exhibited an impaired sensitivity to the activating stimuli, consistent with a significant contribution of this protein domain to channel function. At variance with TRPV1, voltage-dependent gating of chimeric channels could not be detected in the absence of capsaicin and/or heat. Biophysical analysis of functional chimeras revealed that the TRP domain appears to act as a molecular determinant of the activation energy of channel gating. Together, these findings uncover a role of the TRP domain in intersubunit interactions near the channel gate that contribute to the coupling of stimulus sensing to channel opening.
García-Sanz
Nuria
N
Instituto de Biología Molecular y Celular, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain.
Valente
Pierluigi
P
Gomis
Ana
A
Fernández-Carvajal
Asia
A
Fernández-Ballester
Gregorio
G
Viana
Felix
F
Belmonte
Carlos
C
Ferrer-Montiel
Antonio
A
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D002460:Cell Line; D005260:Female; D006801:Humans; D015640:Ion Channel Gating / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000502:physiology; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D021381:Protein Transport / Q000235:genetics / Q000502:physiology; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014981:Xenopus
D010446:Peptide Fragments; D021122:Protein Subunits; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse