The prolyl isomerase, FKBP25, interacts with RNA-engaged nucleolin and the pre-60S ribosomal subunit.
Peptidyl-proline isomerases of the FK506-binding protein (FKBP) family belong to a class of enzymes that catalyze the cis-trans isomerization of prolyl-peptide bonds in proteins. A handful of FKBPs are found in the nucleus, implying that the isomerization of proline in nuclear proteins is enzymatically controlled. FKBP25 is a nuclear protein that has been shown to associate with chromatin modifiers and transcription factors. In this study, we performed the first proteomic characterization of FKBP25 and found that it interacts with numerous ribosomal proteins, ribosomal processing factors, and a small selection of chromatin modifiers. In agreement with previous reports, we found that nucleolin is a major FKBP25-interacting protein and demonstrated that this interaction is dependent on rRNA. FKBP25 interacts with the immature large ribosomal subunit in nuclear extract but does not associate with mature ribosomes, implicating this FKBP's action in ribosome biogenesis. Despite engaging nascent 60S ribosomes, FKBP25 does not affect steady-state levels of rRNAs or its pre-rRNA intermediates. We conclude that FKBP25 is likely recruited to preribosomes to chaperone one of the protein components of the ribosome large subunit.
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada.
Geoff
G
Gudavicius
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada.
David
D
Dilworth
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia V8Z7X8, Canada.
Jason J
JJ
Serpa
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia V8Z7X8, Canada.
Nicole
N
Sessler
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia V8Z7X8, Canada.
Evgeniy V
EV
Petrotchenko
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia V8Z7X8, Canada.
Christoph H
CH
Borchers
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P5C2, Canada.
Christopher J
CJ
Nelson
D002467:Cell Nucleus / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D011498:Protein Precursors / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism*; D012339:RNA, Ribosomal, 28S / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D054683:Ribosome Subunits, Large, Eukaryotic / Q000378:metabolism*; D022021:Tacrolimus Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000097796:Nucleolin
D019696:Peptidylprolyl Isomerase; D010750:Phosphoproteins; D011498:Protein Precursors; D012322:RNA Precursors; D012335:RNA, Ribosomal; D012339:RNA, Ribosomal, 28S; D016601:RNA-Binding Proteins; D022021:Tacrolimus Binding Proteins; D000097796:Nucleolin; C074856:FKBP3 protein, human
FK506 binding protein; nucleolin; nucleus; ribosome biogenesis