MT-TS2 encodes mitochondrial tRNA-Ser(AGY), one of the 22 transfer RNAs encoded by mitochondrial DNA. After excision from the polycistronic mtDNA transcript and post-transcriptional maturation, it is charged with serine by the corresponding mitochondrial aminoacyl-tRNA synthetase and, in the mitochondrial matrix, acts as the adaptor that reads the serine codons AGU and AGC (AGY) of the 13 mtDNA-encoded mRNAs on the mitoribosome, delivering serine to the growing polypeptide. It lacks the entire D-arm, an unusual structure among tRNAs, yet still functions in translation on the mitoribosome, although with lower activity than tRNA-Ser(UCN) in vitro. It is one of two mitochondrial serine isoacceptors (the other is encoded by MT-TS1). Pathogenic variants in MT-TS2, like those in other mt-tRNA genes, impair mitochondrial translation and oxidative phosphorylation and cause maternally inherited mitochondrial disease.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0030533 triplet codon-amino acid adaptor activity | TAS | NEW | Summary: No GOA annotation exists for MT-TS2 (RNAcentral/Rfam2GO supplies GO:0030533 for some but not all mt-tRNA sequences). Proposed to record the canonical tRNA adaptor function. Reason: MT-TS2 is one of the 22 mtDNA-encoded tRNAs used by the mitochondrial translation machinery; the codon-anticodon adaptor function is carried out by the tRNA itself. The same term is assigned by Rfam2GO to sister mt-tRNAs (e.g. MT-TQ, MT-TH, MT-TS1). Supporting Evidence: PMID:11737263 Both mt tRNASerGCU and tRNASerUGA analogues with unusual secondary structure were found to be capable of translation on the ribosome. PMID:21910628 These mRNAs are translated by the mitochondrial protein synthesis machinery, which uses the 22 species of mitochondrial tRNAs (mt tRNAs) encoded by mtDNA. |
| GO:0032543 mitochondrial translation | TAS | NEW | Summary: Proposed process annotation for the mitochondrial tRNA. Reason: The tRNA directly performs the decoding step of mitochondrial translation (it is not merely required for it), so involved_in mitochondrial translation is appropriate; this is the specific child of translation that sister mt-tRNAs receive via the MODIFY of their IEA translation annotation. Supporting Evidence: PMID:11737263 Both mt tRNASerGCU and tRNASerUGA analogues with unusual secondary structure were found to be capable of translation on the ribosome. PMID:21910628 These mRNAs are translated by the mitochondrial protein synthesis machinery, which uses the 22 species of mitochondrial tRNAs (mt tRNAs) encoded by mtDNA. |
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Download this section (compressed HTML)Q: Should GO annotate all 22 mtDNA-encoded tRNAs, including MT-TS2, uniformly to triplet codon-amino acid adaptor activity and mitochondrial translation, rather than relying on Rfam2GO coverage that varies between mt-tRNA sequences?
Suggested experts: GO RNA annotation curators
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