ABSTRACT

Transient receptor potential (TRP) ion channels play diverse and prominent roles in sensory physiology, and dysregulation in function is known to result in various human diseases. Among those that are implicated in disease, the gene encoding TRPP subfamily member polycystin-2 (PC2) is known to harbor mutations that cause autosomal dominant polycystic kidney disease (ADPKD). As a homomeric complex, and in a heteromeric complex with polycystin-1 (PC1), it is speculated to play crucial roles in regulating Ca2+ signaling; however, its activation mechanism remains ambiguous, which makes functional investigation challenging. In order to study the electrophysical characteristics and function of this ion channel and its complexes, we generated a gain-of-function (GOF) mutant of PC2 and measured its channel activity with the two-electrode voltage clamp (TEVC) method. The TEVC method is widely applied for electrophysiological investigation and analysis, and this technique has greatly facilitated our study of PC2 channel function and properties. In this chapter, we describe the use of the TEVC method for GOF mutants of PC2, which bypasses the gating of this channel and opens a new avenue for studying the function and regulation of PC2 and potentially the PC1/2 complex.