Molecular chaperone Hsp90 stabilizes Pih1/Nop17 to maintain R2TP complex activity that regulates snoRNA accumulation.
Hsp90 is a highly conserved molecular chaperone that is involved in modulating a multitude of cellular processes. In this study, we identify a function for the chaperone in RNA processing and maintenance. This functionality of Hsp90 involves two recently identified interactors of the chaperone: Tah1 and Pih1/Nop17. Tah1 is a small protein containing tetratricopeptide repeats, whereas Pih1 is found to be an unstable protein. Tah1 and Pih1 bind to the essential helicases Rvb1 and Rvb2 to form the R2TP complex, which we demonstrate is required for the correct accumulation of box C/D small nucleolar ribonucleoproteins. Together with the Tah1 cofactor, Hsp90 functions to stabilize Pih1. As a consequence, the chaperone is shown to affect box C/D accumulation and maintenance, especially under stress conditions. Hsp90 and R2TP proteins are also involved in the proper accumulation of box H/ACA small nucleolar RNAs.
Zhao
Rongmin
R
Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Kakihara
Yoshito
Y
Gribun
Anna
A
Huen
Jennifer
J
Yang
Guocheng
G
Khanna
May
M
Costanzo
Michael
M
Brost
Renée L
RL
Boone
Charles
C
Hughes
Timothy R
TR
Yip
Christopher M
CM
Houry
Walid A
WA
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics*; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D020537:RNA, Small Nucleolar / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D046911:Macromolecular Substances; D018832:Molecular Chaperones; D009687:Nuclear Proteins; C497702:PIH1 protein, S cerevisiae; D020537:RNA, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C499592:TAH11 protein, S cerevisiae; D014157:Transcription Factors; D000251:Adenosine Triphosphatases; C428198:RVB1 protein, S cerevisiae; C428199:RVB2 protein, S cerevisiae; D004265:DNA Helicases