The ATPase and helicase activities of Prp43p are stimulated by the G-patch protein Pfa1p during yeast ribosome biogenesis.
Prp43p is a RNA helicase required for pre-mRNA splicing and for the synthesis of large and small ribosomal subunits. The molecular functions and modes of regulation of Prp43p during ribosome biogenesis remain unknown. We demonstrate that the G-patch protein Pfa1p, a component of pre-40S pre-ribosomal particles, directly interacts with Prp43p. We also show that lack of Gno1p, another G-patch protein associated with Prp43p, specifically reduces Pfa1p accumulation, whereas it increases the levels of the pre-40S pre-ribosomal particle component Ltv1p. Moreover, cells lacking Pfa1p and depleted for Ltv1p show strong 20S pre-rRNA accumulation in the cytoplasm and reduced levels of 18S rRNA. Finally, we demonstrate that Pfa1p stimulates the ATPase and helicase activities of Prp43p. Truncated Pfa1p variants unable to fully stimulate the activity of Prp43p fail to complement the 20S pre-rRNA processing defect of Deltapfa1 cells depleted for Ltv1p. Our results strongly suggest that stimulation of ATPase/helicase activities of Prp43p by Pfa1p is required for efficient 20S pre-rRNA-to-18S rRNA conversion.
Lebaron
Simon
S
Centre National de la Recherche Scientifique, Laboratoire de Biologie Moléculaire Eucaryote, Toulouse, France.
Papin
Christophe
C
Capeyrou
Régine
R
Chen
Yan-Ling
YL
Froment
Carine
C
Monsarrat
Bernard
B
Caizergues-Ferrer
Michèle
M
Grigoriev
Mikhail
M
Henry
Yves
Y
D000251:Adenosine Triphosphatases / Q000737:chemistry*; D053487:DEAD-box RNA Helicases / Q000378:metabolism / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000737:chemistry; D015966:Gene Expression Regulation, Fungal; D008954:Models, Biological; D010751:Phosphopyruvate Hydratase / Q000502:physiology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020365:RNA Helicases / Q000737:chemistry*; D012322:RNA Precursors / Q000737:chemistry; D012335:RNA, Ribosomal / Q000737:chemistry; D012337:RNA, Ribosomal, 18S / Q000737:chemistry; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism* / Q000502:physiology
C501335:LTV1 protein, S cerevisiae; C546353:PFA1 protein, S cerevisiae; D012322:RNA Precursors; D012335:RNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; D019204:GTP-Binding Proteins; C109034:PRP43 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases; D010751:Phosphopyruvate Hydratase