The Hsp90 chaperone controls the biogenesis of L7Ae RNPs through conserved machinery.

Séverine Boulon (1) , Nathalie Marmier-Gourrier (2) , Bérengère Pradet-Balade (1) , Laurence Wurth (3) , Céline Verheggen (1) , Beáta E Jády (4) , Benjamin Rothé (2) , Christina Pescia (1) , Marie-Cécile Robert (1) , Tamás Kiss (4) , Barbara Bardoni (5) , Alain Krol (3) , Christiane Branlant (2) , Christine Allmang (3) , Edouard Bertrand (1) , Bruno Charpentier (2)

1 IGMM - Institut de Génétique Moléculaire de Montpellier
2 MAEM - Maturation des ARN et enzymologie moléculaire
3 ARN - Architecture et réactivité de l'ARN
4 LBME - Laboratoire de biologie moléculaire eucaryote
5 IGBMC - Institut de génétique et biologie moléculaire et cellulaire

RNA-binding proteins of the L7Ae family are at the heart of many essential ribonucleoproteins (RNPs), including box C/D and H/ACA small nucleolar RNPs, U4 small nuclear RNP, telomerase, and messenger RNPs coding for selenoproteins. In this study, we show that Nufip and its yeast homologue Rsa1 are key components of the machinery that assembles these RNPs. We observed that Rsa1 and Nufip bind several L7Ae proteins and tether them to other core proteins in the immature particles. Surprisingly, Rsa1 and Nufip also link assembling RNPs with the AAA + adenosine triphosphatases hRvb1 and hRvb2 and with the Hsp90 chaperone through two conserved adaptors, Tah1/hSpagh and Pih1. Inhibition of Hsp90 in human cells prevents the accumulation of U3, U4, and telomerase RNAs and decreases the levels of newly synthesized hNop58, hNHP2, 15.5K, and SBP2. Thus, Hsp90 may control the folding of these proteins during the formation of new RNPs. This suggests that Hsp90 functions as a master regulator of cell proliferation by allowing simultaneous control of cell signaling and cell growth.

Domaines: Biochimie, Biologie Moléculaire

Séverine Boulon, Nathalie Marmier-Gourrier, Bérengère Pradet-Balade, Laurence Wurth, Céline Verheggen, et al.. The Hsp90 chaperone controls the biogenesis of L7Ae RNPs through conserved machinery.. Journal of Cell Biology, 2008, 180 (3), pp.579-95. ⟨10.1083/jcb.200708110⟩. ⟨hal-00280860⟩