Mitochondrial poly(A) polymerase and polyadenylation

►Mitochondrial polyadenylation regulates RNA function and metabolism. ►Mitochondrial polyadenylation occurs in higher eukaryotes. ►Human mitochondrial poly(A) polymerase (PAPD1) is a noncanonical PAP. ►The structure of PAPD1 provides molecular insights into its catalysis.