Premium
The role of Hsp90‐R2TP complex in snoRNP assembly and ribosomal RNA processing
Author(s) -
Houry Walid A
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.90.2
Subject(s) - small nucleolar rna , biogenesis , nucleoplasm , biology , chaperone (clinical) , microbiology and biotechnology , ribosomal rna , rna , genetics , nucleolus , long non coding rna , medicine , gene , pathology , cytoplasm
Box C/D snoRNPs, which typically consist of a snoRNA and four protein components (Nop1, Nop56, Nop58 and Snu13), play an essential role in the modification and processing of pre‐rRNA. Earlier, we had demonstrated that the Hsp90‐R2TP (Rvb1‐Rvb2‐Tah1‐Pih1) complex is involved in box C/D snoRNP biogenesis and assembly and, consequently, influences pre‐rRNA processing. Rvb1 and Rvb2 are AAA+ helicases, while Tah1 and Pih1 are Hsp90 cofactors/interactors. We had shown that the stability of the R2TP complex is modulated by Hsp90. More recently, we found, unexpectedly, that the activity of the R2TP complex is controlled by the dynamic subcellular redistribution of its protein components in response to growth conditions and nutrient limitation. In vigorously growing cells, the R2TP complex localizes in the nucleoplasm and interacts tightly with box C/D snoRNPs through Pih1, whereas, this interaction is significantly reduced in poorly growing cells. The R2TP complex is found to affect snoRNP levels by stabilizing Nop58. Our data suggest the presence of an unconventional communication pathway in which the Hsp90 chaperone stabilizes and promotes the assembly of the R2TP complex which in turn stabilizes and promotes the assembly of the box C/D snoRNP complexes. Our progress in this regard will be described in addition to our ongoing efforts aimed at the structural characterization of the R2TP complex.