Nuclear export and retention signals in the RS domain of SR proteins.
Splicing factors of the SR protein family share a modular structure consisting of one or two RNA recognition motifs (RRMs) and a C-terminal RS domain rich in arginine and serine residues. The RS domain, which is extensively phosphorylated, promotes protein-protein interactions and directs subcellular localization and-in certain situations-nucleocytoplasmic shuttling of individual SR proteins. We analyzed mutant versions of human SF2/ASF in which the natural RS repeats were replaced by RD or RE repeats and compared the splicing and subcellular localization properties of these proteins to those of SF2/ASF lacking the entire RS domain or possessing a minimal RS domain consisting of 10 consecutive RS dipeptides (RS10). In vitro splicing of a pre-mRNA that requires an RS domain could take place when the mutant RD, RE, or RS10 domain replaced the natural domain. The RS10 version of SF2/ASF shuttled between the nucleus and the cytoplasm in the same manner as the wild-type protein, suggesting that a tract of consecutive RS dipeptides, in conjunction with the RRMs of SF2/ASF, is necessary and sufficient to direct nucleocytoplasmic shuttling. However, the SR protein SC35 has two long stretches of RS repeats, yet it is not a shuttling protein. We demonstrate the presence of a dominant nuclear retention signal in the RS domain of SC35.
Cazalla
Demian
D
MRC Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, Scotland.
Zhu
Jun
J
Manche
Lisa
L
Huber
Elisabeth
E
Krainer
Adrian R
AR
Cáceres
Javier F
JF
D016475:3T3 Cells; D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D003593:Cytoplasm / Q000378:metabolism; D006367:HeLa Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D015388:Organelles / Q000378:metabolism; D010766:Phosphorylation; D017434:Protein Structure, Tertiary / Q000502:physiology; D012326:RNA Splicing; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D000068103:Serine-Arginine Splicing Factors; D013329:Structure-Activity Relationship; D014162:Transfection
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C499372:SRSF2 protein, mouse; C073288:SRSF2 protein, human; D000068103:Serine-Arginine Splicing Factors