Ribosomal RNA-processing protein 8 (RRP8)

Ribosomal RNA-processing protein 8 (RRP8), also known as nucleomethylin (NML), is a highly conserved nucleolar methyltransferase enzyme essential for ribosome biogenesis. RRP8 catalyzes N¹-methyladenosine (m¹A) modification in rRNA (28S rRNA in humans; 25S rRNA in yeast), a modification critical for the formation of functional 60S ribosomal subunits. Beyond its methyltransferase activity, RRP8/NML coordinates ribosome production with nutrient availability via the energy-dependent nucleolar silencing complex, affecting rRNA transcription and cellular proliferation. Loss of RRP8 disrupts ribosome assembly, activates p53, and leads to cell cycle arrest. In humans, RRP8 also functions as an autoantigen in systemic lupus erythematosus, especially lupus nephritis, highlighting its relevance for autoimmunity and potential use as a biomarker.

Other names

NucleomethylinKIAA0409NMLCerebral protein 1hucep-1RRP8 methyltransferase homolog (S. cerevisiae)ribosomal RNA processing 8 methyltransferase homolognucleomethylincerebral protein 1

Not applicable (no direct drugs); likely mechanisms for a potential inhibitor would involve inhibition of methyltransferase activity, leading to defects in ribosomal subunit maturation and altered cell proliferation.