PTRH2 (peptidyl-tRNA hydrolase 2), also known as BIT1, is a mitochondrial protein. During apoptosis, PTRH2 is released from the mitochondria to the cytoplasm. Once in the cytoplasm, PTRH2 regulates the function of two transcriptional regulators, TLE5 and TLE1, thereby promoting caspase-independent cell death. The natural substrate for PTRH2 may be petidyl-tRNAs which drop off the ribosome during protein synthesis.