TRAP150 interacts with the RNA-binding domain of PSF and antagonizes splicing of numerous PSF-target genes in T cells.
PSF (a.k.a. SFPQ) is a ubiquitously expressed, essential nuclear protein with important roles in DNA damage repair and RNA biogenesis. In stimulated T cells, PSF binds to and suppresses the inclusion of CD45 exon 4 in the final mRNA; however, in resting cells, TRAP150 binds PSF and prevents access to the CD45 RNA, though the mechanism for this inhibition has remained unclear. Here, we show that TRAP150 binds a region encompassing the RNA recognition motifs (RRMs) of PSF using a previously uncharacterized, 70 residue region we have termed the PSF-interacting domain (PID). TRAP150's PID directly inhibits the interaction of PSF RRMs with RNA, which is mediated through RRM2. However, interaction of PSF with TRAP150 does not appear to inhibit the dimerization of PSF with other Drosophila Behavior, Human Splicing (DBHS) proteins, which is also dependent on RRM2. Finally, we use RASL-Seq to identify ∼40 T cell splicing events sensitive to PSF knockdown, and show that for the majority of these, PSF's effect is antagonized by TRAP150. Together these data suggest a model in which TRAP150 interacts with dimeric PSF to block access of RNA to RRM2, thereby regulating the activity of PSF toward a broad set of splicing events in T cells.
Department of Biochemistry and Biophysics Perelman, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Christopher A
CA
Yarosh
Department of Biochemistry and Biophysics Perelman, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Iulia
I
Tapescu
Department of Biochemistry and Biophysics Perelman, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Matthew G
MG
Thompson
Department of Cell and Molecular Medicine, University of California, San Diego, San Diego, CA 92093, USA.
Jinsong
J
Qiu
Department of Biochemistry and Biophysics Perelman, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Michael J
MJ
Mallory
Department of Cell and Molecular Medicine, University of California, San Diego, San Diego, CA 92093, USA.
Xiang-Dong
XD
Fu
Department of Biochemistry and Biophysics Perelman, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA klync@mail.med.upenn.edu.
Kristen W
KW
Lynch
D017398:Alternative Splicing; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D000072670:PTB-Associated Splicing Factor; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D013601:T-Lymphocytes; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*
D004268:DNA-Binding Proteins; D000072670:PTB-Associated Splicing Factor; D016601:RNA-Binding Proteins; C475774:THRAP3 protein, human; D014157:Transcription Factors; D012313:RNA