Disease relevance of SPB1

• We have identified a new type of S-adenosyl-L-methionine-dependent methyltransferase in the cytosol of Escherichia coli that is expressed in early stationary phase under the control of the RpoS sigma factor [1].

High impact information on SPB1

• Spb1p-directed formation of Gm2922 in the ribosome catalytic center occurs at a late processing stage [2].
• Functional redundancy of Spb1p and a snR52-dependent mechanism for the 2'-O-ribose methylation of a conserved rRNA position in yeast [3].
• We demonstrate that a point mutation in the Ado-Met binding site of Spb1p affects cell growth but does not abolish methylation of U2918 [3].
• Protein sequence analysis reveals that Spb1p possesses a putative S-adenosyl-L-methionine (AdoMet)-binding domain, which is common to the AdoMet-dependent methyltransferases [4].
• The structure of PPM1 reveals a common S-adenosyl-l-methionine-dependent methyltransferase fold, with several insertions conferring the specific function and substrate recognition [5].

Biological context of SPB1

• A Saccharomyces servazzii clone homologous to Saccharomyces cerevisiae chromosome III spanning KAR4, ARS 304 and SPB1 lacks the recombination enhancer but contains an unknown ORF [6].
• These results suggest that Spb1p is involved in 60S ribosomal subunit biogenesis and associates early with the pre-ribosomes [7].

Anatomical context of SPB1

• We present here the characterization of SPB1, an essential yeast gene that is required for ribosome synthesis [4].
• Polysome analyses showed an under-accumulation of 60S ribosomal subunits in the spb1-1 mutant and in a strain genetically depleted of Spb1p [7].

Other interactions of SPB1

• Consistent with this, hemagglutinin epitope-tagged Spb1p localizes to the nucleus with nucleolar enrichment [7].

References