In the absence of ligand, NTRK3 (TRKC) is cleaved by an unknown caspase. CASP3 (caspase-3) cleaves NTRK3 in vitro, but CASP3 inhibitors do not prevent NTRK3 cleavage in live cells. CASP8 (caspase-8) is unable to cleave NTRK3 in vitro. A general caspase inhibitor prevents NTRK3 cleavage in live cells (Tauszig-Delamasure et al. 2007).