PXD026894

PXD026894 is an original dataset announced via ProteomeXchange.

Title	Phosphorylation regulates arginine-rich RNA-binding protein solubility and oligomerization
Description	Post-translational modifications (PTMs) within splicing factor RNA-binding proteins (RBPs), such as phosphorylation, regulate several critical steps in RNA metabolism including spliceosome assembly, alternative splicing and mRNA export. Notably, the arginine-/serine-rich (RS) domains in SR proteins are densely modified by phosphorylation compared with the remainder of the proteome. Previously, we showed that dephosphorylation of SRSF2 regulated increased interactions with similar arginine-rich RBPs U1-70K and LUC7L3. In this work, we dephosphorylated nuclear extracts using phosphatase in vitro and analyzed equal amounts of detergent-soluble and -insoluble fractions by mass spectrometry-based proteomics. Correlation network analysis resolved 27 distinct modules of differentially soluble nucleoplasm proteins. We found classes of arginine-rich RBPs that decrease in solubility following dephosphorylation and enrich to the insoluble pelleted fraction, including the SR protein family and the SR-like LUC7L RBP family. However, increased insolubility was not observed across broad classes of RBPs. Phosphorylation regulated SRSF2 structure, as dephosphorylated SRSF2 formed high molecular weight oligomeric species in vitro. Reciprocally, phosphorylation of SRSF2 by serine-/arginine protein kinase 2 (SRPK2) in vitro prevented high molecular weight SRSF2 species formation. Furthermore, we pharmacologically inhibited SRPKs in mammalian cells and observed increased cytoplasmic granules as well as the formation of cytoplasmic SRSF2 tubular structures that associate with microtubules by immunocytochemical staining. Collectively, these findings demonstrate that phosphorylation may be a critical modification that prevents arginine-rich RBP insolubility and oligomerization.
HostingRepository	PRIDE
AnnounceDate	2021-11-02
AnnouncementXML	Submission_2021-11-02_06:33:16.446.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Sean Kundinger
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	phosphorylated residue
Instrument	Orbitrap Fusion Lumos

Revision	Datetime	Status	ChangeLog Entry
0	2021-06-23 22:08:21	ID requested
⏵ 1	2021-11-02 06:33:16	announced

Dataset with its publication pending

submitter keyword: RNA-binding proteins, phosphorylation, post-translational modifications, mass spectrometry, protein interactions, SRSF2, SC35

Nicholas T. Seyfried
contact affiliation	Department of Biochemistry, Emory University, Atlanta, GA, USA Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
contact email	nseyfri@emory.edu
lab head
Sean Kundinger
contact affiliation	Emory University
contact email	skundin@emory.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD026894
     1. Label: PRIDE project
     2. Name: Phosphorylation regulates arginine-rich RNA-binding protein solubility and oligomerization