The C-terminal tail of ribosomal protein Rps15 is engaged in cytoplasmic pre-40S maturation

Abstract

The small ribosomal subunit protein Rps15/uS19 is involved in early nucleolar ribosome biogenesis and subsequent nuclear export of pre-40S particles to the cytoplasm. In addition, the C-terminal tail of Rps15 was suggested to play a role in mature ribosomes, namely during translation elongation. Here, we show that Rps15 not only functions in nucleolar ribosome assembly but also in cytoplasmic pre-40S maturation, which is indicated by a strong genetic interaction between Rps15 and the 40S assembly factor Ltv1. Specifically, mutations either in the globular or C-terminal domain of Rps15 when combined with the non-essential ltv1 null allele are lethal or display a strong growth defect. However, not only rps15 ltv1 double mutants but also single rps15 C-terminal deletion mutants exhibit an accumulation of the 20S pre-rRNA in the cytoplasm, indicative of a cytoplasmic pre-40S maturation defect. Since in pre-40S particles, the C-terminal tail of Rps15 is positioned between assembly factors Rio2 and Tsr1, we further tested whether Tsr1 is genetically linked to Rps15, which indeed could be demonstrated. Thus, the integrity of the Rps15 C-terminal tail plays an important role during late pre-40S maturation, perhaps in a quality control step to ensure that only 40S ribosomal subunits with functional Rps15 C-terminal tail can efficiently enter translation. As mutations in the C-terminal tail of human RPS15 have been observed in connection with chronic lymphocytic leukaemia, it is possible that apart from defects in translation, an impaired late pre-40S maturation step in the cytoplasm could also be a reason for this disease.

Role of Flt3l and Rps15 in ketamine anesthesia

“…The ribosome consists of various ribosomal proteins, including Rps15, which collaborate to translate RNA information into proteins. [24] The positioning and function of Rps15 within the ribosome are crucial for protein synthesis. Rps15 is located on the small subunit of the ribosome, where it interacts with ribosomal RNA and other ribosomal proteins, contributing to the structural composition of the ribosome.…”

The value of RPS15 and MRPS27 in ischemic stroke

“…In addition, the C-terminal tail of RPS15 is thought to play a role in mature ribosomes, that is, in the process of translation elongation. [ 20 ] Recent studies have found that RPS15 not only plays a role in ribosome assembly, but also before cytoplasmic 40 seconds maturation. Changes in nucleoli (ribosome production site) have long been associated with cancer, and mutations in several RP are associated with an increased risk of cancer in human diseases.…”