Homo sapiens Protein: PNPT1
InnateDB Protein IDBP-376583.4
Last Modified 2014-10-13 [Report errors or provide feedback]
Gene Symbol PNPT1
Protein Name polyribonucleotide nucleotidyltransferase 1
Species Homo sapiens
Ensembl Protein ENSP00000393953
InnateDB Gene IDBG-52626 (PNPT1)
Protein Structure
UniProt Annotation
Function 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. 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. {ECO:0000269PubMed:12473748, ECO:0000269PubMed:12721301, ECO:0000269PubMed:12798676, ECO:0000269PubMed:16055741, ECO:0000269PubMed:16410805, ECO:0000269PubMed:16934922, ECO:0000269PubMed:18083836, ECO:0000269PubMed:18083837, ECO:0000269PubMed:18501193, ECO:0000269PubMed:19509288, ECO:0000269PubMed:20547861, ECO:0000269PubMed:20691904}.
Subcellular Localization Cytoplasm. Mitochondrion. Mitochondrion intermembrane space; Peripheral membrane protein.
Disease Associations Combined oxidative phosphorylation deficiency 13 (COXPD13) [MIM:614932]: A mitochondrial disorder characterized by early onset severe encephalomyopathy, dystonia, choreoathetosis, bucofacial dyskinesias and combined mitochondrial respiratory chain deficiency. Nerve conductions velocities are decreased. Levels of plasma and cerebrospinal fluid lactate are increased. {ECO:0000269PubMed:23084291}. Note=The disease is caused by mutations affecting the gene represented in this entry.Deafness, autosomal recessive, 70 (DFNB70) [MIM:614934]: A form of non-syndromic deafness characterized by severe, bilateral hearing impairment with prelingual onset, resulting in inability to acquire normal speech. {ECO:0000269PubMed:23084290}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Tissue Specificity
Number of Interactions This gene and/or its encoded proteins are associated with 18 experimentally validated interaction(s) in this database.
Experimentally validated
Total 18 [view]
Protein-Protein 18 [view]
Protein-DNA 0
Protein-RNA 0
Gene Ontology

Molecular Function
Accession GO Term
GO:0000175 3'-5'-exoribonuclease activity
GO:0003676 nucleic acid binding
GO:0003723 RNA binding
GO:0004654 polyribonucleotide nucleotidyltransferase activity
GO:0005515 protein binding
GO:0008266 poly(U) RNA binding
GO:0034046 poly(G) binding
GO:0035198 miRNA binding
GO:0044822 poly(A) RNA binding
Biological Process
GO:0000957 mitochondrial RNA catabolic process
GO:0000958 mitochondrial mRNA catabolic process
GO:0000962 positive regulation of mitochondrial RNA catabolic process
GO:0000964 mitochondrial RNA 5'-end processing
GO:0000965 mitochondrial RNA 3'-end processing
GO:0006396 RNA processing
GO:0006401 RNA catabolic process
GO:0006402 mRNA catabolic process
GO:0034599 cellular response to oxidative stress
GO:0035458 cellular response to interferon-beta
GO:0035927 RNA import into mitochondrion
GO:0035928 rRNA import into mitochondrion
GO:0043457 regulation of cellular respiration
GO:0043631 RNA polyadenylation
GO:0045926 negative regulation of growth
GO:0051260 protein homooligomerization
GO:0061014 positive regulation of mRNA catabolic process
GO:0070207 protein homotrimerization
GO:0070584 mitochondrion morphogenesis
GO:0071042 nuclear polyadenylation-dependent mRNA catabolic process
GO:0071850 mitotic cell cycle arrest
GO:0090503 RNA phosphodiester bond hydrolysis, exonucleolytic
GO:0097222 mitochondrial mRNA polyadenylation
GO:2000627 positive regulation of miRNA catabolic process
GO:2000772 regulation of cellular senescence
Cellular Component
GO:0005737 cytoplasm
GO:0005739 mitochondrion
GO:0005758 mitochondrial intermembrane space
GO:0016020 membrane
GO:0045025 mitochondrial degradosome
Protein Structure and Domains
InterPro IPR001247 Exoribonuclease, phosphorolytic domain 1
IPR003029 Ribosomal protein S1, RNA-binding domain
IPR004087 K Homology domain
IPR004088 K Homology domain, type 1
IPR012162 Polyribonucleotide nucleotidyltransferase
IPR012340 Nucleic acid-binding, OB-fold
IPR015847 Exoribonuclease, phosphorolytic domain 2
IPR015848 Polyribonucleotide nucleotidyltransferase, RNA-binding domain
IPR020568 Ribosomal protein S5 domain 2-type fold
IPR022967 RNA-binding domain, S1
PFAM PF01138
Post-translational Modifications
SwissProt Q8TCS8
PhosphoSite PhosphoSite-Q8TCS8
UniProt Splice Variant
Entrez Gene 87178
UniGene Hs.673273
OMIM 610316
HPRD 18493
EMBL AC015982 AJ458465 AY027528 AY290863 BC000862 BC005986 BC053660 CR749867
GenPept AAH00862 AAH05986 AAH53660 AAK13047 AAP44472 AAY24271 CAD30289 CAH18709