Rpf2Rrs1

Rpf2Rrs1 refers to the functional complex formed by the ribosome biogenesis factors Rpf2 and Rrs1 in eukaryotes. In many yeast species and other organisms, Rpf2 and Rrs1 form a stable heterodimer that acts during the maturation of the large ribosomal subunit. The complex is essential for proper assembly of the 60S subunit and the incorporation of key RNA and ribosomal components.

In the ribosome biogenesis pathway, the Rpf2-Rrs1 heterodimer associates with early pre-60S particles in the nucleolus and nucleus. It participates in the processing and stabilization steps that enable the correct placement of 5S ribosomal RNA into the growing pre-60S subunit, a process closely linked to the coordinated assembly of ribosomal proteins such as L5. Loss or disruption of Rpf2-Rrs1 function blocks 5S rRNA processing and prevents progression to mature 60S subunits, causing accumulation of immature pre-rRNA species and defects in ribosome production.

Localization and evolutionary conservation: The Rpf2-Rrs1 heterodimer is conserved across eukaryotes, including fungi and animals, and is viewed as a core component of the early pre-60S particle. In humans, homologous proteins labeled RPF2 and RRS1 participate in analogous ribosome biogenesis steps, supporting a conserved mechanism for 60S subunit maturation and nucleolar organization.

Structure and interactions: The two proteins interact to form a functional unit that engages with pre-60S assembly factors and ribosomal RNA components. This interaction network stabilizes the incorporation of 5S rRNA into the assembling subunit and integrates Rpf2-Rrs1 activity with other maturation factors during ribosome biogenesis. Impaired function of this complex can contribute to nucleolar stress and broader defects in cell growth.