Table 9.
Factors involved in cytoplasmic pre‐40S maturation.
| Yeast | 40S | 60S | Human | 40S | 60S | Function in cytoplasmic pre‐40S maturation | Citation |
|---|---|---|---|---|---|---|---|
| Enp1 | x | ENP1/BYSL | x | Released by Hrr25/CKI phosphorylation, Release allows stable incorporation of Rps3/uS3, Rps10/eS10 and Rps20/uS10, Formation of the beak structure | Schäfer et al (2006), Zemp et al (2014) and Ameismeier et al (2018) | ||
| Ltv1 | x | LTV1 | x | ||||
| Tsr1 | x | TSR1 | x | Released, occludes binding sites for mRNA and translation initiation factors | Larburu et al (2016) and Scaiola et al (2018) | ||
| Dim1 | x | DIMT1 | x | Methyltransferase, yeast: modifies subsequent adenines near 3′ end of 18S rRNA; human: function occurs already in the nucleus | Strunk et al (2011) and Zorbas et al (2015) | ||
| Rrp12 | x | RRP12 | x | Released, which allows incorporation of Asc1 (RACK1 in humans) | Wyler et al (2011) and Larburu et al (2016) | ||
| Dim2/Pno1 | x | PNO1/DIM2 | x | Inhibits binding of eIF3; release contributes to Major structural rearrangements, allowing Nob1 activity | Ameismeier et al (2018) and Scaiola et al (2018) | ||
| Nob1 | x | NOB1 | x | Endonucleolytic cleavage of 20S pre‐rRNA (18S‐E pre‐rRNA in humans) to yield mature 18S rRNA | Fatica et al (2003) and Lamanna and Karbstein (2011) | ||
| Hrr25 | x | CKI‐δ/CSNK1D | x | Phosphorylation of Enp1‐Ltv1‐Rps3/uS3 complex, which triggers release of Ltv1 | Schäfer et al (2006) and Zemp et al (2014) | ||
| CKI‐ε/CSNK1E | x | ||||||
| Rio1 | x | RIOK1/RIO1 | x | Orchestrates structural changes, pre‐rRNA maturation and trans‐acting factor release | Vanrobays et al (2003) and Widmann et al (2012) | ||
| Rio2 | x | RIOK2/RIO2 | x | Kinase contributes to pre‐rRNA maturation and trans‐acting factor release | Geerlings et al (2003) and Zemp et al (2009) | ||
| RIOK3 | x | Promotes 18S‐E processing | Geerlings et al (2003) | ||||
| Prp43 | x | DHX15 | Conformational pre‐rRNA switch, which allows Nob1 activity | Pertschy et al (2009) | |||
| Pfa1/Sqs1 | x | SON | x | Cofactor for Prp43 | Sloan et al (2013b) | ||
| Pxr1/Gno1 | x | PINX1 | x | Cofactor for Prp43 | Guglielmi and Werner (2002) and Chen et al (2014) | ||
| Hbs1 | x | HBS1 | In yeast: facilitates formation of 80S like particle | Lebaron et al (2012), Strunk et al (2012) and Hector et al (2014) | |||
| Dom34 | x | PELO | |||||
| Rli1 | x | ABCE1 | |||||
| Fun12 | x | EIF5B | |||||
| USP16 | x | Deubiquitylates lysine 113 in RPS27A/eS31 | Montellese et al (2020) | ||||
| LRRC47 | x | Bound to late cytoplasmic pre‐40S particle | Ameismeier et al (2020) | ||||
| EIF1AD | x | Supports trans‐acting factor release and pre‐rRNA maturation | Ameismeier et al (2020) |