Identification of an snRNP-associated kinase activity that phosphorylates arginine/serine rich domains typical of splicing factors

Woppmann, Andreas; Will, Cindy L.; Kornstädt, Ute; Zuo, Ping; Manley, James L.; Lührmann, Reinhard

doi:10.1093/nar/21.12.2815

Cited by 88 publications

(65 citation statements)

References 30 publications

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“…A number of mammalian kinases have been shown to cause disassembly of nuclear speckles and relocalization of splicing factors, and to subsequently affect splicing factor activity. SRPK-1/2, Clk-1/2/3/4, cdc2-kinase, cyclin Ecdk2, topoisomerase I, U1 70-kDa associated kinase, cGMPdependent kinase, and lamin B-receptor kinase were all shown to phosphorylate SR proteins and other splicing factors in vitro (Woppmann et al, 1993;Gui et al, 1994;Colwill et al, 1996;Nikolakaki et al, 1996;Rossi et al, 1996;Nayler et al, 1997;Duncan et al, 1998;Kuroyanagi et al, 1998;Okamoto et al, 1998;Seghezzi et al, 1998;Wang et al, 1998;Koizumi et al, 1999;Wang et al, 1999). In addition, some of these kinases were shown to affect the splicing activity of such factors (Mermoud et al, 1994;Cao et al, 1997;Xiao and Manley, 1998;Prasad et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Nuclear Relocalization of the Pre-mRNA Splicing Factor PSF during Apoptosis Involves Hyperphosphorylation, Masking of Antigenic Epitopes, and Changes in Protein Interactions

Shav‐Tal

Cohen

Lapter

et al. 2001

MBoC

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The spatial nuclear organization of regulatory proteins often reflects their functional state. PSF, a factor essential for pre-mRNA splicing, is visualized by the B92 mAb as discrete nuclear foci, which disappeared during apoptosis. Because this mode of cell death entails protein degradation, it was considered that PSF, which like other splicing factors is sensitive to proteolysis, might be degraded. Nonetheless, during the apoptotic process, PSF remained intact and was N-terminally hyperphosphorylated on serine and threonine residues. Retarded gel migration profiles suggested differential phosphorylation of the molecule in mitosis vs. apoptosis and under-phosphorylation during blockage of cells at G1/S. Experiments with the use of recombinant GFP-tagged PSF provided evidence that in the course of apoptosis the antigenic epitopes of PSF are masked and that PSF reorganizes into globular nuclear structures. In apoptotic cells, PSF dissociated from PTB and bound new partners, including the U1-70K and SR proteins and therefore may acquire new functions. INTRODUCTIONSplicing factors are found within the nucleus both in a diffuse form and in distinct domains termed interchromatin granules (IG) or "speckles" (Spector, 1993). These functional compartments are spatially dynamic with regard to movement and composition (Eils et al., 2000). Splicing factors within IGs are highly mobile and are constantly associating and dissociating from their compartments (Phair and Misteli, 2000). The mAb, B92, which recognizes the polypyrimidine tract binding protein (PTB)-associated splicing factor (PSF), produces typical specked nuclear pattern in immunostaining. These PSF speckles disappear during granulocytic differentiation (Lee et al., 1996;Shav-Tal et al., 2000). We recently showed that this disappearance is associated with partial degradation (Shav-Tal et al., 2000) and by the formation of alternative nuclear structures (Shav-Tal et al., 2001). The present study indicates that PSF speckles disappear also through a different mechanism, involving conformational changes that cause breakdown of PSF speckles and relocalization of the molecule in the nucleus. The functional nature of speckles is a matter of some controversy (for review, see Park and De Boni, 1999). These structures have been suggested to play a role in storage and recycling of splicing factors (Jimenez-Garcia and Spector, 1993), whereas a portion may act as reservoirs for the recruitment to active sites of transcription (Huang and Spector, 1996;Zeng et al., 1997). This view does not predict a direct involvement of speckles in pre-mRNA splicing. On the other hand, it has been shown that nascent mRNA transcripts and transcription sites are closely associated with speckles, that transcription occurs at the surface of speckles (Clemson and Lawrence, 1996), and that microinjected pre-mRNAs have high affinity to speckles (Wang et al., 1991). It has thus been proposed that speckles can act coordinately in transcription and splicing and that pre-mRNA splicing can take place bo...

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Section: Discussionmentioning

confidence: 99%

Nuclear Relocalization of the Pre-mRNA Splicing Factor PSF during Apoptosis Involves Hyperphosphorylation, Masking of Antigenic Epitopes, and Changes in Protein Interactions

Shav‐Tal

Cohen

Lapter

et al. 2001

MBoC

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“…In the nucleus, factors involved in pre-mRNA processing are concentrated in speckles-dynamic structures (Misteli et al, 1997) that are sensitive to phosphorylation (Nayler et al, 1998b). A number of kinases, phosphorylating RS domains, have been described, among them a U1 70K-associated kinase (Woppmann et al, 1993), SRPK1 (Gui et al, 1993), and SRPK2 (Wang et al, 1998). In addition, four kinases termed CLK (cdc2-like kinases) have been shown to phosphorylate SR proteins and to regulate their subnuclear localization (Colwill et al, 1996a,b;Nayler et al, 1997Nayler et al, , 1998b.…”

Section: Introductionmentioning

confidence: 99%

Regulation of Alternative Splicing of Human Tau Exon 10 by Phosphorylation of Splicing Factors

Hartmann

Rujescu

Giannakouŕos

et al. 2001

Molecular and Cellular Neuroscience

103

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“…6 At least 11-13 natural variants of the U1-70K protein, partially due to phosphorylation, have been found by 2D analysis. 7,8 However, very little is known about specific phosphorylated residues in this protein or specific enzymes involved in the functional regulation of the U1-70K protein by phosphorylation/dephosphorylation.Apoptosis is a fast and orderly process consisting of a sequence of steps, depending on the inducer, in which caspases play a central role. Especially caspase-3 cleaves many proteins involved in important cellular processes, such as transcription, mRNA splicing/processing and translation.…”

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confidence: 99%

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Apoptosis-linked changes in the phosphorylation status and subcellular localization of the spliceosomal autoantigen U1-70K

et al. 2008

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Apoptosis consists of highly regulated pathways involving post-translational modifications and cleavage of proteins leading to sequential inactivation of the main cellular processes. Here, we focused on the apoptotic processing of one of the essential components of the mRNA splicing machinery, the U1-70K snRNP protein. We found that at an early stage of apoptosis, before the cleavage of the C-terminal part of the protein by caspase-3, the basal phosphorylation of the Ser140 residue located within the RNA recognition motif, increases very significantly. A caspase-dependent, PP1-mediated dephosphorylation of other serine residues takes place in a subset of U1-70K proteins. The U1-70K protein phosphorylated at Ser140 is clustered in heterogeneous ectopic RNP-derived structures, which are finally extruded in apoptotic bodies. The elaborate processing of the spliceosomal U1-70K protein we identified might play an important role in the regulated breakdown of the mRNA splicing machinery during early apoptosis. In addition, these specific changes in the phosphorylation/dephosphorylation balance and the subcellular localization of the U1-70K protein might explain why the region encompassing the Ser140 residue becomes a central autoantigen during the autoimmune disease systemic lupus erythematosus. Cell Death and Differentiation (2008) In higher eukaryotes, the process of gene expression includes transcription, pre-mRNA splicing/processing and translation in the cytoplasm. The macromolecular machinery involved in pre-mRNA splicing, the spliceosome, consists of five small nuclear ribonucleoparticles (snRNPs) called U1, U2 and U4-6 snRNP, and a large number of additional splicing factors. 1 Splicing factors are supposedly recruited from storage sites, that is interchromatin granules, in the interchromatin space to transcription sites at the periphery of condensed chromatin. The assembly of the spliceosome is initiated by recognition of the 5 0 splice site of pre-mRNA by U1 snRNP and mediated by serine/arginine-rich (SR) proteins. 2 Phosphorylation and dephosphorylation both have an important role in the recruitment of splicing factors and the subsequent regulation of spliceosome assembly and splicing catalysis. 3 The U1-snRNP-specific U1-70K protein is a highly phosphorylated protein, which contains two SR domains. Phosphorylation of both the SR protein ASF/SF2 and the first SR domain of the U1-70K protein are involved in vitro in their interaction. 4,5 In addition, thiophosphorylation of the U1-70K protein, making it resistant to dephosphorylation by phosphatases, results in complete inhibition of splicing, but not of spliceosome formation. 6 At least 11-13 natural variants of the U1-70K protein, partially due to phosphorylation, have been found by 2D analysis. 7,8 However, very little is known about specific phosphorylated residues in this protein or specific enzymes involved in the functional regulation of the U1-70K protein by phosphorylation/dephosphorylation.Apoptosis is a fast and orderly process consisting of a seq...

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Identification of an snRNP-associated kinase activity that phosphorylates arginine/serine rich domains typical of splicing factors

Cited by 88 publications

References 30 publications

Nuclear Relocalization of the Pre-mRNA Splicing Factor PSF during Apoptosis Involves Hyperphosphorylation, Masking of Antigenic Epitopes, and Changes in Protein Interactions

Nuclear Relocalization of the Pre-mRNA Splicing Factor PSF during Apoptosis Involves Hyperphosphorylation, Masking of Antigenic Epitopes, and Changes in Protein Interactions

Regulation of Alternative Splicing of Human Tau Exon 10 by Phosphorylation of Splicing Factors

Apoptosis-linked changes in the phosphorylation status and subcellular localization of the spliceosomal autoantigen U1-70K

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