Temperature-induced opening of TRPV1 ion channel is stabilized by the pore domain.
TRPV1 is the founding and best-studied member of the family of temperature-activated transient receptor potential ion channels (thermoTRPs). Voltage, chemicals and heat allosterically gate TRPV1. Molecular determinants of TRPV1 activation by capsaicin, allicin, acid, ammonia and voltage have been identified. However, the structures and mechanisms mediating TRPV1's pronounced temperature sensitivity remain unclear. Recent studies of the related channel TRPV3 identified residues in the pore region that are required for heat activation. We used both random and targeted mutagenesis screens of rat TRPV1 and identified point mutations in the outer pore region that specifically impair temperature activation. Single-channel analysis indicated that TRPV1 mutations disrupted heat sensitivity by ablating long channel openings, which are part of the temperature-gating pathway. We propose that sequential occupancy of short and long open states on activation provides a mechanism for enhancing temperature sensitivity. Our results suggest that the outer pore is important for the heat sensitivity of thermoTRPs.
Grandl
Jörg
J
Department of Cell Biology, Scripps Research Institute, La Jolla, California, USA.
Kim
Sung Eun
SE
Uzzell
Valerie
V
Bursulaya
Badry
B
Petrus
Matt
M
Bandell
Michael
M
Patapoutian
Ardem
A
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D006801:Humans; D015640:Ion Channel Gating; D007700:Kinetics; D008564:Membrane Potentials; D008954:Models, Biological; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D018408:Patch-Clamp Techniques; D017354:Point Mutation; D011336:Probability; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D050916:TRPV Cation Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013696:Temperature
D050505:Mutant Proteins; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat