Conserved Site

Bacterial Fmu (Sun)/eukaryotic nucleolar NOL1/Nop2p, conserved site (IPR018314)

Short name: Fmu/NOL1/Nop2p_CS


This pattern is to a conserved central domain which contains some highly conserved regions, and which is found in archaeal, bacterial and eukaryotic proteins.

In the archaea and bacteria, they are annotated as putative nucleolar protein, Sun (Fmu) family protein or tRNA/rRNA cytosine-C5-methylase. The majority have the S-adenosyl methionine (SAM) binding domain and are related to Escherichia coli Fmu (Sun) protein (16S rRNA m5C 967 methyltransferase) whose structure has been determined [PMID: 14656444].

In the eukaryota, the majority are annotated as being 'hypothetical protein', nucleolar protein or the Nop2/Sun (Fmu) family. Unlike their bacterial homologues, few of the eukaryotic members in this family have a the SAM binding signature. Despite this, Saccharomyces cerevisiae (Baker's yeast) Nop2p is a probable RNA m5C methyltransferase [PMID: 12872006]. It is essential for processing and maturation of 27S pre-rRNA and large ribosomal subunit biogenesis [PMID: 12872006]; localized to the nucleolus and is essential for viability [PMID: 7806561]. Reduced Nop2p expression limits yeast growth and decreases levels of mature 60S ribosomal subunits while altering rRNA processing [PMID: 8972218]. There is substantial identity between Nop2p and Homo sapiens (Human) p120 (NOL1), which is also called the proliferation-associated nucleolar antigen [PMID: 7806561, PMID: 2576976].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003723 RNA binding
GO:0008168 methyltransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns