SR and SR-related proteins redistribute to segregated fibrillar components of nucleoli in a response to DNA damage

Sakashita, Eiji; Endo, Hitoshi

doi:10.4161/nucl.1.4.12683

Cited by 25 publications

(19 citation statements)

References 78 publications

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“…Indeed, paraspeckles were named for their proximity to, but distinction from, nuclear speckles, and the Cajal body is reported to associate with the nucleolus, HLB, and PML nuclear body (Fox et al, ; Sawyer, Hager, & Dundr, ; Sun, Xu, Subramony, & Hebert, ; Trinkle‐Mulcahy & Sleeman, ). Additionally, many proteins from distinct MLOs are localized to the nucleolar caps during transcriptional inactivation (Fox et al, ; Polak, Simone, Kaberlein, Luo, & Thirman, ; Sakashita & Endo, ; Shav‐Tal et al, ). It is unknown whether these association phenomena are biologically relevant, and few studies have reported the impact of depletion of one nuclear body upon the function of other structures (Tapia et al, ).…”

Section: Mlo Cooperativity and Rna/protein Sharingmentioning

confidence: 99%

Membraneless nuclear organelles and the search for phases within phases

2018

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Cells are segregated into two distinct compartment groups to optimize cellular function. The first is characterized by lipid membranes that encapsulate specific regions and regulate macromolecular flux. The second, known collectively as membraneless organelles (MLOs), lacks defining lipid membranes and exhibits self‐organizing properties. MLOs are enriched with specific RNAs and proteins that catalyze essential cellular processes. A prominent sub‐class of MLOs are known as nuclear bodies, which includes nucleoli, paraspeckles, and other droplets. These microenvironments contain specific RNAs, exhibit archetypal liquid–liquid phase separation characteristics, and harbor intrinsically disordered, multivalent hub proteins. We present an analysis of nuclear body protein disorder that suggests MLO proteomes are significantly more disordered than structured cellular features. We also outline common MLO ultrastructural features, exemplified by the three sub‐compartments present inside the nucleolus. A core‐shell configuration, or phase within a phase, is displayed by several nuclear bodies and may be functionally important. Finally, we summarize evidence indicating extensive RNA and protein sharing between distinct nuclear bodies, suggesting functional cooperation and similar nucleation principles. Considering the substantial accumulation of specific coding and noncoding RNA classes inside MLOs, evidence that RNA buffers specific phase transition events, and the absence of a clear correlation between total intrinsic protein disorder and MLO accumulation, we conclude that RNA biogenesis may play a key role in MLO formation, internal organization, and function. This article is categorized under: RNA Export and Localization > RNA Localization RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications

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Section: Mlo Cooperativity and Rna/protein Sharingmentioning

confidence: 99%

Membraneless nuclear organelles and the search for phases within phases

2018

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“…SR proteins are predominantly located in the nucleus [33][34][35][36][37][38][39] and their nuclear import is mediated by transportin-SR, a member of the b-karyopherin family. This importin specifically contacts the RS domain to convey them through the nuclear pore [40,41].…”

Section: Sr Protein Localization and Nucleo-cytoplasmic Shuttlingmentioning

confidence: 99%

Shuttling SR proteins: more than splicing factors

2011

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Serine-arginine (SR) proteins commonly designate a family of eukaryotic RNA binding proteins containing a protein domain composed of several repeats of the arginine-serine dipeptide, termed the arginine-serine (RS) domain. This protein family is involved in essential nuclear processes such as constitutive and alternative splicing of mRNA precursors. Besides participating in crucial activities in the nuclear compartment, several SR proteins are able to shuttle between the nucleus and the cytoplasm and to exert regulatory functions in the latter compartment. This review aims at discussing the properties of shuttling SR proteins with particular emphasis on their nucleo-cytoplasmic traffic and their cytoplasmic functions. Indeed, recent findings have unravelled the complex regulation of SR protein nucleo-cytoplasmic distribution and the diversity of cytoplasmic mechanisms in which these proteins are involved. SR proteins: definition and general featuresSerine-arginine (SR) proteins were first described as a family of co-purifying proteins capable of restoring splicing in S100 splicing-deficient extracts. These factors are structurally highly related as they are composed of a carboxy-terminal domain enriched with the arginine-serine (RS) dipeptide, preceded by at least one RNA binding domain of the RNA recognition motif (RRM) type [1]. These proteins play an essential role in constitutive and alternative splicing of mRNA precursors [2]. In the last 10 years, however, other functions have been unravelled for these proteins. Indeed, SR protein prototypes such as SRSF1 (ASF ⁄ SF2) and SRSF2 (SC35) were reported to stimulate transcriptional elongation (for a review see [3]). Certain SR proteins participate in mRNA translation (see [4] and below). Finally, a recent study indicates that SRSF1 promotes microRNA processing by facilitating Drosha-mediated cleavage [5]. Altogether, these findings highlight the broader roles of SR proteins in gene expression.Genome-wide searches for proteins containing RS domains revealed several other 'non-classical' SR proteins, termed SR-like proteins because of differences in the structure of the RS domain and ⁄ or lack of a prototypical RRM. While a large subset of SR-like proteins is involved in pre-mRNA processing, several members of this protein family are associated with other cellular functions [4,6].'Classical' SR proteins exist in plants [7], metazoans [1] and in some unicellular eukaryotes, such as the fission yeast Schizosaccharomyces pombe [8,9]. However, they are not present in all eukaryotes and are Abbreviations ARE, AU-rich element; NMD, nonsense-mediated decay; PIAS1, protein inhibitor of activated STAT-1; RRM, RNA recognition motif;

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“…38,39 During stress conditions, nuclear speckles undergo morphological changes, and many splicing factors are redistributed. 40 We therefore examined the co-localization of PDIP38 after UV irradiation with proteins that are known markers for these subcompartments. The markers used were C23 for the nucleolus, PML protein 35 for the PML bodies, and splicing regulator protein SC35 41 for the spliceosomes.…”

Section: Pdip38 Is Recruited To Nuclear Speckles In Response To Uv Irmentioning

confidence: 99%