P0protein

P0 protein, also known as ribosomal acidic protein P0, is a component of the 60S large ribosomal subunit in eukaryotes and many archaea. It forms the base of the ribosomal stalk by partnering with the acidic P1 and P2 proteins, creating a protruding stalk that helps recruit translation factors during protein synthesis. In this context, P0 is considered homologous to the bacterial L10 protein, and the eukaryotic stalk typically consists of P0 bound to two P1–P2 heterodimers.

Gene and expression information is conserved across eukaryotes. In humans and many other vertebrates, the P0 protein is encoded by the RPLP0 gene. The protein is broadly expressed and essential for cell viability, reflecting its central role in assembling and maintaining an active ribosome.

Structure and interactions are characteristic of its function. P0 is relatively acidic and contains regions that contribute to ribosome binding and to the formation of the stalk. The N-terminal portion helps anchor the protein to the 60S subunit, while the highly acidic C-terminal tail engages with P1 and P2 proteins. The flexible stalk region serves as a platform for interactions with elongation factors.

Function and role in translation are central to its conservation. The P0-containing ribosomal stalk facilitates the interaction of the ribosome with eukaryotic translation factors, such as eEF1A and eEF2, promoting efficient GTP hydrolysis and the progression of protein synthesis.

Clinical and research notes: Alterations in ribosomal stalk components, including P0, have been linked to certain cancers and ribosomopathies in some contexts, though the specific effects of P0 can vary. P0’s high conservation and essential role make it a focus of studies on ribosome structure and function.