MTPAP polyadenylates mitochondrial mRNA

Stable Identifier
R-HSA-9936998
Type
Reaction [transition]
Species
Homo sapiens
Compartment
mitochondrial matrix
ReviewStatus
3/5
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MTPAP polyadenylates mitochondrial mRNA
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MTPAP (PAPD1) polymerizes relatively short polyadenylate tails of 40-50 nucleotides onto the 3' ends of mitochondrial mRNAs (Nagaike et al. 2005, Slomovic and Schuster 2008, Bai et al. 2011, Wilson et al. 2014). For comparison, cytosolic mRNAs have polyadenylate tails of about 250 nucleotides (reviewed in Boreikaitė and Passmore 2023). Dimerization of MTPAP is required for its polyadenylation activity (Bai et al. 2011). Knocking down mitochondrial polynucleotide nucleotidyltransferase 1 (PNPT1, PNPase) causes lengthening of the polyadenylate tails, therefore PNPT1 may act as a deadenylase that counteracts MTPAP (Nagaike et al. 2005). In the absence of MTPAP, mRNAs are observed to retain oligoadenylated tails of about 15 adenylate residues (Slomovic and Schuster 2008, Wilson et al. 2014), raising the possibility that mitochondria have an unidentified enzyme that performs oligoadenylation. The N478D mutation in human MTPAP causes respiratory chain defects, spastic ataxia, and optic atrophy (Wilson et al. 2014). Positive regulation of mitochondrial polyadenylation by LPRRC is observed in human mitochondria (Chujo et al. 2012, Wilson et al. 2014) and in mice (Ruzzenente et al. 2012).
Literature References
PubMed ID Title Journal Year
18083837 Stable PNPase RNAi silencing: its effect on the processing and adenylation of human mitochondrial RNA

Slomovic, S, Schuster, G

RNA 2008
21292163 Structural basis for dimerization and activity of human PAPD1, a noncanonical poly(A) polymerase

Bai, Y, Srivastava, SK, Chang, JH, Manley, JL, Tong, L

Mol Cell 2011
25008111 A human mitochondrial poly(A) polymerase mutation reveals the complexities of post-transcriptional mitochondrial gene expression

Wilson, WC, Hornig-Do, HT, Bruni, F, Chang, JH, Jourdain, AA, Martinou, JC, Falkenberg, M, Spåhr, H, Larsson, NG, Lewis, RJ, Hewitt, L, Baslé, A, Cross, HE, Tong, L, Lebel, RR, Crosby, AH, Chrzanowska-Lightowlers, ZM, Lightowlers, RN

Hum Mol Genet 2014
15769737 Human mitochondrial mRNAs are stabilized with polyadenylation regulated by mitochondria-specific poly(A) polymerase and polynucleotide phosphorylase

Nagaike, T, Suzuki, T, Katoh, T, Ueda, T

J Biol Chem 2005
Participants
Input
Output
Participates
as an event of
Catalyst Activity

poly(A) RNA polymerase activity of MTPAP:Mg2+ dimer [mitochondrial matrix]

Physical Entity
MTPAP:Mg2+ dimer [mitochondrial matrix] (Homo sapiens)
Activity
poly(A) RNA polymerase activity (GO:1990817)
This event is regulated
Positively by
Regulator
SLIRP:LRPPRC [mitochondrial matrix] (Homo sapiens)
Authored
May, B  (2025-01-25)
Created
May, B  (2025-01-28)
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