Cytosolic 80S ribosome (80S ribosome)

The cytosolic 80S ribosome is the primary molecular machine responsible for protein synthesis in eukaryotic cells. It consists of two subunits: the large 60S subunit and the small 40S subunit, which together coordinate the translation of messenger RNA (mRNA) into polypeptide chains [Wikipedia]. Its primary biological function is the translation of genetic information from mRNA into functional proteins, a process involving initiation, elongation, and termination phases [Molecular Biology of the Cell]. In clinical medicine, the 80S ribosome is a therapeutic target for certain cancers; for instance, omacetaxine mepesuccinate binds to the ribosomal A-site to prevent the correct positioning of aminoacyl-tRNA, thereby inhibiting the synthesis of short-lived oncoproteins like BCR-ABL [PubChem, CID 23662344]. Furthermore, the 80S ribosome is the target of various ribosome-inactivating proteins (RIPs) such as ricin, which irreversibly damage the 28S rRNA, and certain antifungal agents that exploit structural differences between human and fungal ribosomes [PubMed, PMID 11433344]. Dysregulation of ribosomal biogenesis or function is associated with ribosomopathies and is often exploited by viruses to prioritize the translation of viral proteins over host proteins [Nature Reviews Genetics, 2019]. Because protein synthesis is essential for all living cells, drugs targeting the 80S ribosome often have a narrow therapeutic index and can cause significant systemic toxicity [StatPearls].

Other names

Eukaryotic ribosome80S ribosomal complexCytoplasmic ribosome

Omacetaxine mepesuccinate binds to the A-site of the 80S ribosome, preventing the initial elongation step of protein synthesis [FDA]. Ribosome-inactivating proteins like ricin depurinate the sarcin/ricin loop of the 28S rRNA, halting translation [PubMed, PMID 11433344].