Pre-rRNA-processing protein TSR1 homolog (TSR1)

TSR1 is a critical factor in the biogenesis of the small (40S) ribosomal subunit in both yeast and mammals. It is essential for the final cytoplasmic steps of 40S subunit maturation, where it binds to pre-40S particles and stabilizes them, preventing premature association with the 60S subunit and blocking access to maturation factors like eIF5B and Rio1 until the appropriate stage[1]. Despite its structural similarity to GTPases, TSR1 does not bind GTP or hydrolyze it, indicating it functions as a structural rather than enzymatic factor[1]. Depletion of TSR1 disrupts processing of the internal transcribed spacer 1 (ITS1), leading to accumulation of 18S rRNA precursors and retention of pre-40S particles in the nucleus[3]. In addition to its core role in ribosome assembly, TSR1 is implicated in congenital cataract due to a splicing mutation in a Chinese family, and its expression is developmentally regulated in the lens; it may also influence MAPK-Erk signaling in lens development[3]. However, there is no strong evidence linking TSR1 to cardiovascular disease or other major pathologies outside of ribosome maturation and lens development[3].

Other names

Pre-40S ribosome biogenesis factor Tsr1KIAA1401FLJ1053420S rRNA accumulation 1TSR1_HUMANpre-rRNA-processing protein TSR1 homolog