Stress induced subcellular distribution of ALG-2, RBM22 and hSlu7.
ALG-2 is a highly conserved calcium binding protein in the cytoplasm which belongs to the family of penta-EF hand proteins. Recently, we showed that ALG-2 is interacting with RBM22, a highly conserved spliceosomal nuclear protein (Montaville et al. Biochim. Biophys. Acta 1763, 1335, 2006; Krebs, Biochim. Biophys. Acta 1793, 979, 2009). In NIH 3T3 cells expressing both proteins a significant amount of ALG-2mRFP is translocated to the nucleus due to the interaction with RBM22-EGFP. hSlu7, another spliceosomal nuclear protein, known to interact with RBM22 in yeast, has been shown to translocate to the cytoplasm under cellular stress conditions. Here we provide evidence that the 2 spliceosomal proteins differ significantly in their subcellular distributions under stress conditions, and that RBM22 enhances the cytoplasmic translocation of hSlu7 under stress, especially a stress induced by thapsigargin. On the other hand, in NIH 3T3 cells expressing RBM22-EGFP and ALG-2-mRFP, ALG-2 remains translocated into the nucleus under both stress conditions, i.e. heat shock or treatment with thapsigargin. We could further demonstrate that these stress conditions had a different influence on the splicing pattern of XBP-1, a marker for the unfolded protein response indicating that ER stress may play a role in stress-induced translocation of spliceosomal proteins. The article is part of a Special Issue entitled: 11th European Symposium on Calcium.
Department of Biochemistry, School of Molecular and Systems Biology, University of Alberta, Edmonton, Canada.
Aleksandra
A
Janowicz
Marek
M
Michalak
Joachim
J
Krebs
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D057075:Enzyme Assays; D018869:Heat-Shock Response / Q000187:drug effects; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D021381:Protein Transport / Q000187:drug effects; D012326:RNA Splicing / Q000187:drug effects; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000378:metabolism*; D000071701:Regulatory Factor X Transcription Factors; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics; D000071717:X-Box Binding Protein 1
D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D000071701:Regulatory Factor X Transcription Factors; D017411:Ribonucleoproteins, Small Nuclear; C490656:SLU7 protein, human; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse; D019284:Thapsigargin; D008156:Luciferases