8.A.64 The Phosphoinositide-interacting Protein (PIRT) Family
PIRT is considered to be a regulatory subunit of various transient recptor potential (Trp) channels. For example, TRPV1, a molecular sensor of noxious heat and capsaicin, is positively regulated by PIRT and phosphatidylinositol 4,5-bisphosphate (PIP2) and other phosphoinositides, but not phosphatidylinositol (PI). Pirt and PIP2 also synergistically enhance TRPM8 channel activity by increasing the single channel conductance (Tang et al. 2015). Pirt is a molecular sensor of noxious heat and capsaicin. It positively regulates TRPV1 channel activity via phosphatidylinositol 4,5-bisphosphate (PIP2) and binds various phosphoinositides, including phosphatidylinositol 4,5-bisphosphate (PIP2), but not phosphatidylinositol. Moreover, Pirt is an endogenous regulator of the ATP-activated P2X3 channel (TC# 1.A.7.1.6) in bladder cells (Gao et al. 2015).