FEATURES

FAMILY

polyribonucleotide nucleotidyltransferase family

DESCRIPTION

Also known as PNPT1_HUMAN, PNPT1, PNPASE. RNA-binding protein implicated in numerous RNA metabolic processes. Catalyzes the phosphorolysis of single-stranded polyribonucleotides processively in the 3'-to-5' direction. Mitochondrial intermembrane factor with RNA-processing exoribonulease activity. Component of the mitochondrial degradosome (mtEXO) complex, that degrades 3' overhang double-stranded RNA with a 3'-to-5' directionality in an ATP-dependent manner. Involved in the degradation of non-coding mitochondrial transcripts (MT-ncRNA) and tRNA-like molecules (PubMed:29967381). Required for correct processing and polyadenylation of mitochondrial mRNAs. Plays a role as a cytoplasmic RNA import factor that mediates the translocation of small RNA components, like the 5S RNA, the RNA subunit of ribonuclease P and the mitochondrial RNA-processing (MRP) RNA, into the mitochondrial matrix. Plays a role in mitochondrial morphogenesis and respiration; regulates the expression of the electron transport chain (ETC) components at the mRNA and protein levels. In the cytoplasm, shows a 3'-to-5' exoribonuclease mediating mRNA degradation activity; degrades c-myc mRNA upon treatment with IFNB1/IFN-beta, resulting in a growth arrest in melanoma cells. Regulates the stability of specific mature miRNAs in melanoma cells; specifically and selectively degrades miR-221, preferentially. Plays also a role in RNA cell surveillance by cleaning up oxidized RNAs. Binds to the RNA subunit of ribonuclease P, MRP RNA and miR-221 microRNA. Homotrimer; in free form (PubMed:19509288). Homooligomer (PubMed:19509288). Component of the mitochondrial degradosome (mtEXO) complex which is a heteropentamer containing 2 copies of SUPV3L1 and 3 copies of PNPT1 (PubMed:19509288, PubMed:29967381). As part of the mitochondrial degradosome complex, interacts with GRSF1 in an RNA-dependent manner; the interaction enhances the activity of the complex (PubMed:29967381). Interacts with TCL1A; the interaction has no effect on PNPT1 exonuclease activity (PubMed:16934922).

EXTERNAL LINKS

PNPT1

Polyribonucleotide nucleotidyltransferase 1, mitochondrial

PNPT1

Molecular Synopsis