PTH2, also known as PTRH2, is a mitochondrial protein which belongs to the PTH2 family. PTH 2 is released during apoptosis from the mitochondria to the cytoplasm. The natural substrate for PTH 2 may be peptidyl-tRNAs which drop off the ribosome during protein synthesis. When in the cytoplasm, PTRH2 regulates the function of 2 transcriptional regulators, TLE5 and TLE1, thus promoting caspase-independent cell death.