Fibrillarin

Fibrillarin is a protein that plays a critical role in the biogenesis of ribosomes, which are the cellular structures responsible for protein synthesis. Fibrillarin is located in the nucleolus of the cell, a region where ribosome production occurs. It is involved in the chemical modification of ribosomal RNA (rRNA), specifically in the methylation of rRNA, which is a crucial step in the maturation of ribosomal subunits.

Fibrillarin is a component of small nucleolar ribonucleoproteins (snoRNPs), which are essential for the processing and modification of pre-rRNA. The protein interacts with small nucleolar RNAs (snoRNAs) and is part of the complex that catalyzes the 2'-O-methylation of ribose sugars in rRNA. This modification is important for the proper folding and function of rRNA within the ribosome.

The gene encoding fibrillarin, often referred to as FBL, is highly conserved across eukaryotes, highlighting the essential role of this protein in cell biology. Mutations or dysregulation of fibrillarin can lead to various cellular dysfunctions and has been associated with diseases such as cancer and autoimmune diseases. For instance, high levels of fibrillarin expression have been observed in certain types of cancer, suggesting a potential role in tumorigenesis. Additionally, autoantibodies against fibrillarin are a marker for a specific form of autoimmune disease known as systemic sclerosis.

Research into fibrillarin not only provides insights into the fundamental processes of ribosome assembly and function but also offers potential targets for therapeutic intervention in diseases associated with ribosome biogenesis dysregulation.