Mitochondrial polymerase processivity subunit. It regulates the polymerase and exonuclease activities promoting processive DNA synthesis. Binds to ss-DNA. Heterotrimer composed of a catalytic subunit and a homodimer of accessory subunits. The disease is caused by variants affecting the gene represented in this entry. The disease may be caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry.