Our Research

The capsaicin receptor

TRPV1 is the first identified heat sensor. It was discovered by Dr. David Julius and colleagues at UCSF as a receptor for capsaicin, the chemical compound that gives chili peppers the spicy taste. When capsaicin binds to TRPV1, it opens the channel and elicits the “hot” sensation just like heat does. This is because excitation of specific sensory neurons encodes hotness, no matter the excitation is caused physically (by heat) or chemically (by capsaicin). Other thermoTRPs share many structural features with TRPV1 (e.g., they are TRPV1 homologs); however, they are not sensitive to capsaicin. Also, TRPV1 of certain animals such as birds are not capsaicin-sensitive. Our work shows that, in the TRPV1 protein, heat and capsaicin do not share the same activation pathway (see Figure 2) (Yang et al. PNAS, 2010; Cui et al. JGP, 2012). Experimental perturbations to heat-induced activation often leave capsaicin-induced activation largely unchanged. We also demonstrate that heteromeric channels made of two TRPV1 subunits and two TRPV3 subunits remain capsaicin sensitive, even though in these channels there are only two capsaicin-binding subunits (Cheng, Yang, et al. JBC, 2012).

img src="../images/research/figure-2-big.jpg" width="650" height="488" alt="The capsaicin receptor" />

Figure 2 legend: Separation of capsaicin and heat activation pathways. Only the pore-forming regions of two subunits are shown.