Related Experiment Video
Updated: Feb 28, 2026

Novel RNA-Binding Proteins Isolation by the RaPID Methodology
Published on: September 30, 2016
SR proteins: To shuttle or not to shuttle, that is the question
Marie-Louise Hammarskjold1,2, David Rekosh3,2
1Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA mh7g@virginia.edu.
Serine- and arginine-rich proteins (SR proteins) like SRSF2 and SRSF5 shuttle to the cytoplasm with messenger RNA in pluripotent cells. This shuttling does not occur in differentiated cells, revealing a novel aspect of SR protein function.
Area of Science:
- Molecular Biology
- Cell Biology
- Gene Regulation
Background:
- Serine- and arginine-rich (SR) proteins are crucial for RNA processing events, including splicing, nuclear export, and translation.
- SR proteins are typically localized to the nucleus, where they perform essential regulatory functions.
Purpose of the Study:
- To investigate the subcellular localization and dynamics of specific SR proteins (SRSF2 and SRSF5) in pluripotent versus differentiated cells.
- To determine if SR proteins shuttle between the nucleus and cytoplasm and if this behavior is cell-type dependent.
Main Methods:
- Utilized pluripotent P19 cells and their differentiated counterparts.
- Employed techniques to track the movement of SR proteins (SRSF2 and SRSF5) in relation to messenger RNA.
Main Results:
- SRSF2 and SRSF5, previously considered exclusively nuclear, were observed to shuttle with messenger RNA from the nucleus to the cytoplasm.
- This nuclear-cytoplasmic shuttling of SRSF2 and SRSF5 was specific to pluripotent P19 cells.
- The shuttling behavior was absent in differentiated P19 cells.
Conclusions:
- SRSF2 and SRSF5 exhibit dynamic nucleocytoplasmic shuttling in pluripotent cells, a behavior not observed in differentiated cells.
- This finding suggests a novel role for these SR proteins in regulating gene expression during cellular differentiation.
- The cell-type specific localization and transport of SR proteins may be critical for maintaining pluripotency.
Related Concept Videos
Directing Proteins to the Rough Endoplasmic Reticulum
Post-translational Translocation of Proteins to the RER
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Cotranslational Protein Translocation
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Regulation of Nuclear Protein Sorting
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Overview of Protein Sorting and Transport
Protein sorting can be of two types: signal-based sorting and vesicle-based trafficking. In signal-based sorting, specific amino acid sequences called sorting signals target proteins to the proper location inside the cell either via gated transport or by protein translocation. In gated transport, folded...

