Pta1 is a conserved noncatalytic component of the nuclear cleavage and polyadenylation factor complex. It supports cotranscriptional mRNA 3β²-end formation and the coupling of RNA cleavage and polyadenylation to RNA polymerase II transcription termination. Its role is organization of the processing machinery, whose cleavage endonuclease and poly(A) polymerase are separate subunits.
Reason: No independently demonstrated catalytic molecular activity is assigned to this CPF scaffold. The ND root term records an unresolved molecular function and is not evidence against its established biological-process role.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ...
ACCEPT
Summary: nucleus is supported.
Reason: Pta1 is a constituent of the nuclear cotranscriptional cleavage and polyadenylation machinery, consistent with the curated localization screen.
Next, we determined the localization of 4,431 proteins, corresponding to approximately 90% of the fission yeast proteome, by tagging each ORF with the yellow fluorescent protein.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
Reason: Pta1 is a constituent of the nuclear cotranscriptional cleavage and polyadenylation machinery, consistent with the curated localization screen.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
NAS PMID:33711009 Structure-function analysis of fission yeast cleavage and po...
ACCEPT
Summary: nucleus is supported.
Reason: Pta1 is a constituent of the nuclear cotranscriptional cleavage and polyadenylation machinery, consistent with the curated localization screen.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
GO:0005847 mRNA cleavage and polyadenylation specificity factor complex
IBA GO_REF:0000033
ACCEPT
Summary: mRNA cleavage and polyadenylation specificity factor complex is supported.
Reason: Fission yeast CPF contains Pta1 in its ten-subunit core. The original proteomic study underlies PomBase complex membership; the accessible CPF study explicitly lists Pta1 and distinguishes it from the catalytic Ysh1 and Pla1 subunits.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
GO:0005847 mRNA cleavage and polyadenylation specificity factor complex
IDA PMID:14617822 A comparative analysis of an orthologous proteomic environme...
ACCEPT
Summary: mRNA cleavage and polyadenylation specificity factor complex is supported.
Reason: Fission yeast CPF contains Pta1 in its ten-subunit core. The original proteomic study underlies PomBase complex membership; the accessible CPF study explicitly lists Pta1 and distinguishes it from the catalytic Ysh1 and Pla1 subunits. The original PMID:14617822 annotation is retained at its stated evidential scope; accessible source text and the independent evidence cited here are considered together.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
GO:0005847 mRNA cleavage and polyadenylation specificity factor complex
NAS PMID:33711009 Structure-function analysis of fission yeast cleavage and po...
ACCEPT
Summary: mRNA cleavage and polyadenylation specificity factor complex is supported.
Reason: Fission yeast CPF contains Pta1 in its ten-subunit core. The original proteomic study underlies PomBase complex membership; the accessible CPF study explicitly lists Pta1 and distinguishes it from the catalytic Ysh1 and Pla1 subunits.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
Summary: tRNA processing is retained as an ancillary annotation.
Reason: Budding yeast pta1 mutants accumulate intron-containing pre-tRNAs, supporting the curated orthology-based tRNA-processing association. Extracts retain normal tRNA-splicing endonuclease activity, so this phenotype does not establish Pta1 as a tRNA nuclease or make tRNA processing its principal conserved biochemical role.
PTA1 was initially defined by a UV-induced mutation, pta1-1, that causes the accumulation of all 10 end-trimmed, intron-containing pre-tRNAs and temperature-sensitive but osmotic-remedial growth.
Extracts prepared from pta1 mutant strains are impaired in the cleavage and the poly(A) addition of both GAL7 and CYC1 substrates and exhibit little processing activity even after prolonged incubation. However, activity is efficiently rescued by the addition of purified CF II to the defective extracts.
GO:0030846 termination of RNA polymerase II transcription, poly(A)-coupled
NAS PMID:33711009 Structure-function analysis of fission yeast cleavage and po...
ACCEPT
Summary: termination of RNA polymerase II transcription, poly(A)-coupled is supported.
Reason: CPF executes cotranscriptional mRNA 3β² processing before termination; Pta1 is an established core subunit. Complementation of defective budding yeast pta1 extracts establishes conserved participation in cleavage and poly(A) addition. The inference concerns complex participation, not intrinsic nuclease or polymerase activity.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
Extracts prepared from pta1 mutant strains are impaired in the cleavage and the poly(A) addition of both GAL7 and CYC1 substrates and exhibit little processing activity even after prolonged incubation. However, activity is efficiently rescued by the addition of purified CF II to the defective extracts.
GO:0180010 co-transcriptional mRNA 3'-end processing, cleavage and polyadenylation pathway
IC GO_REF:0000111
ACCEPT
Summary: co-transcriptional mRNA 3'-end processing, cleavage and polyadenylation pathway is supported.
Reason: CPF executes cotranscriptional mRNA 3β² processing before termination; Pta1 is an established core subunit. Complementation of defective budding yeast pta1 extracts establishes conserved participation in cleavage and poly(A) addition. The inference concerns complex participation, not intrinsic nuclease or polymerase activity.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
Extracts prepared from pta1 mutant strains are impaired in the cleavage and the poly(A) addition of both GAL7 and CYC1 substrates and exhibit little processing activity even after prolonged incubation. However, activity is efficiently rescued by the addition of purified CF II to the defective extracts.
Core Functions
Noncatalytic CPF subunit organizing mRNA cleavage/polyadenylation and coupled transcription termination.
Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein).
Extracts prepared from pta1 mutant strains are impaired in the cleavage and the poly(A) addition of both GAL7 and CYC1 substrates and exhibit little processing activity even after prolonged incubation. However, activity is efficiently rescued by the addition of purified CF II to the defective extracts.
These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.
Pta1 participates in CPF-mediated mRNA 3β²-end formation; the predicted mRNA-processing role is supported but less precise than this established function.
Review rationale: Pta1 is a component of the experimentally characterized fission yeast CPF core. Purified-factor rescue of budding yeast pta1 mutant extracts establishes its conserved participation in mRNA cleavage and poly(A) addition. GOA already records co-transcriptional mRNA 3β²-end processing, cleavage and polyadenylation pathway (GO:0180010). The broad mRNA-processing prediction is correct but loses the established mechanistic specificity and does not assign intrinsic nuclease activity.
Supporting Evidence:
PMID:33711009: "Holo-CPF consists of two component complexes (Fig 1): a 10-subunit CPF core composed of proteins Ysh1 (the cleavage endonuclease), Pla1 (the poly(A) polymerase), Pta1, Yth1 (a zinc finger protein), Pfs2 (a WD repeat protein), Iss1, Cft1 (a WD repeat protein), Cft2 (a metallo-Ξ²-lactamase/Ξ²-CASP protein), Ctf1, and Ssu72 (a phosphoprotein phosphatase); and a 3-subunit DPS complex comprising Dis2 (a phosphoprotein phosphatase), Ppn1, and Swd22 (a WD repeat protein)."
PMID:10523662: "Extracts prepared from pta1 mutant strains are impaired in the cleavage and the poly(A) addition of both GAL7 and CYC1 substrates and exhibit little processing activity even after prolonged incubation. However, activity is efficiently rescued by the addition of purified CF II to the defective extracts."