Large family of predicted nucleotide-binding domains
SMART accession number:
SM00670
Description:
From similarities to 5'-exonucleases, these domains are predicted to be RNases. PINc domains in nematode SMG-5 and yeast NMD4p are predicted to be involved in RNAi.
PIN domains are small protein domains identified by the presence of three strictly conserved acidic residues. Apart from these three residues, there is poor sequence conservation [ (PUBMED:21036780) ]. PIN domains are found in eukaryotes, eubacteria and archaea. In eukaryotes they are ribonucleases involved in nonsense mediated mRNA decay [ (PUBMED:17053788) ] and in processing of 18S ribosomal RNA [ (PUBMED:19706509) ]. In prokaryotes, they are the toxic components of toxin-antitoxin (TA) systems, their toxicity arising by virtue of their ribonuclease activity. The PIN domain TA systems are now called VapBC TAs(virulence associated proteins), where VapB is the inhibitor and VapC, the PIN-domain ribonuclease toxin [ (PUBMED:21036780) ].
Family alignment:
There are 39194 PINc domains in 39191 proteins in SMART's nrdb database.
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Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing PINc domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with PINc domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing PINc domain in the selected taxonomic class.
Comparative genomics of the Archaea (Euryarchaeota): evolution ofconserved protein families, the stable core, and the variable shell.
Genome Res. 1999; 9: 608-28
Display abstract
Comparative analysis of the protein sequences encoded in the foureuryarchaeal species whose genomes have been sequenced completely(Methanococcus jannaschii, Methanobacterium thermoautotrophicum,Archaeoglobus fulgidus, and Pyrococcus horikoshii) revealed 1326orthologous sets, of which 543 are represented in all four species. Theproteins that belong to these conserved euryarchaeal families comprise31%-35% of the gene complement and may be considered the evolutionarilystable core of the archaeal genomes. The core gene set includes the greatmajority of genes coding for proteins involved in genome replication andexpression, but only a relatively small subset of metabolic functions. Formany gene families that are conserved in all euryarchaea, previouslyundetected orthologs in bacteria and eukaryotes were identified. A numberof euryarchaeal synapomorphies (unique shared characters) were identified;these are protein families that possess sequence signatures or domainarchitectures that are conserved in all euryarchaea but are not found inbacteria or eukaryotes. In addition, euryarchaea-specific expansions ofseveral protein and domain families were detected. In terms of theirapparent phylogenetic affinities, the archaeal protein families split intobacterial and eukaryotic families. The majority of the proteins that haveonly eukaryotic orthologs or show the greatest similarity to theireukaryotic counterparts belong to the core set. The families ofeuryarchaeal genes that are conserved in only two or three speciesconstitute a relatively mobile component of the genomes whose evolutionshould have involved multiple events of lineage-specific gene loss andhorizontal gene transfer. Frequently these proteins have detectableorthologs only in bacteria or show the greatest similarity to thebacterial homologs, which might suggest a significant role of horizontalgene transfer from bacteria in the evolution of the euryarchaeota.
