Signaling-dependent and coordinated regulation of transcription, splicing, and translation resides in a single coregulator, PCBP1.
Transcription, splicing, and translation are potentially coordinately regulatable in a temporospatial-dependent manner, although supporting experimental evidence for this notion is scarce. Yeast two-hybrid screening of a mammary gland cDNA library with human p21-activated kinase 1 (Pak1) as bait identified polyC-RNA-binding protein 1 (PCBP1), which controls translation from mRNAs containing the DICE (differentiation control element). Mitogenic stimulation of human cells phosphorylated PCBP1 on threonines 60 and 127 in a Pak1-sensitive manner. Pak1-dependent phosphorylation of PCBP1 released its binding and translational inhibition from a DICE-minigene. Overexpression of PCBP1 also inhibited the translation of the endogenous L1 cell adhesion molecule mRNA, which contains two DICE motifs in the 3' untranslated region. We also found that Pak1 activation led to an increased nuclear retention of PCBP1, recruitment to the eukaryotic translation initiation factor 4E (eIF4E) promoter, and stimulation of eIF4E expression in a Pak1-sensitive manner. Moreover, mitogenic stimulation promoted Pak1- and PCBP1-dependent alternative splicing and exon inclusion from a CD44 minigene. The alternative splicing functions of PCBP1 were in turn mediated by its intrinsic interaction with Caper alpha, a U2 snRNP auxiliary factor-related protein previously implicated in RNA splicing. These findings establish the principle that a single coregulator can function as a signal-dependent and coordinated regulator of transcription, splicing, and translation.
Meng
Qingchang
Q
Molecular and Cellular Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Rayala
Suresh K
SK
Gururaj
Anupama E
AE
Talukder
Amjad H
AH
O'Malley
Bert W
BW
Kumar
Rakesh
R
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D039561:Eukaryotic Initiation Factor-4E / Q000378:metabolism; D005260:Female; D015723:Gene Library; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000502:physiology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012326:RNA Splicing; D016601:RNA-Binding Proteins; D015398:Signal Transduction; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D054462:p21-Activated Kinases
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D039561:Eukaryotic Initiation Factor-4E; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D018960:Hyaluronan Receptors; C094604:PCBP1 protein, human; D016601:RNA-Binding Proteins; C515903:PAK1 protein, human; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases