title: Proteasome-mediated proteolysis of SRSF5 splicing factor intriguingly co-occurs with SRSF5 mRNA upregulation during late erythroid differentiation.
abstract: SR proteins exhibit diverse functions ranging from their role in constitutive and alternative splicing, to virtually all aspects of mRNA metabolism. These findings have attracted growing interest in deciphering the regulatory mechanisms that control the tissue-specific expression of these SR proteins. In this study, we show that SRSF5 protein decreases drastically during erythroid cell differentiation, contrasting with a concomitant upregulation of SRSF5 mRNA level. Proteasome chemical inhibition provided strong evidence that endogenous SRSF5 protein, as well as protein deriving from stably transfected SRSF5 cDNA, are both targeted to proteolysis as the cells undergo terminal differentiation. Consistently, functional experiments show that overexpression of SRSF5 enhances a specific endogenous pre-mRNA splicing event in proliferating cells, but not in differentiating cells, due to proteasome-mediated targeting of both endogenous and transfection-derived SRSF5. Further investigation of the relationship between SRSF5 structure and its post-translation regulation and function, suggested that the RNA recognition motifs of SRSF5 are sufficient to activate pre-mRNA splicing, whereas proteasome-mediated proteolysis of SRSF5 requires the presence of the C-terminal RS domain of the protein. Phosphorylation of SR proteins is a key post-translation regulation that promotes their activity and subcellular availability. We here show that inhibition of the CDC2-like kinase (CLK) family and mutation of the AKT phosphorylation site Ser86 on SRSF5, have no effect on SRSF5 stability. We reasoned that at least AKT and CLK signaling pathways are not involved in proteasome-induced turnover of SRSF5 during late erythroid development.
authors.affiliation: "mRNA Metabolism in Normal and Pathological Cells"; Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR, Université Lyon 1, Villeurbanne, France.
authors.forename: Osman
authors.initials: O
authors.lastname: Breig
authors.forename: Faouzi
authors.initials: F
authors.lastname: Baklouti
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D041905:Erythroid Cells / Q000166:cytology* / Q000378:metabolism*; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D059748:Proteolysis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D000068103:Serine-Arginine Splicing Factors
chemical_list: D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C585267:SRSF5 protein, mouse; D000068103:Serine-Arginine Splicing Factors; C066780:Clk dual-specificity kinases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D046988:Proteasome Endopeptidase Complex
references.citation: Blood. 2008 Jan 1;111(1):392-401
references.pmid: 17715393
references.citation: Biochem J. 2009 Jan 1;417(1):15-27
references.pmid: 19061484
references.citation: J Virol. 2010 Jul;84(13):6748-59
references.pmid: 20427542
references.citation: Blood. 2001 Dec 15;98(13):3809-16
references.pmid: 11739190
references.citation: EMBO J. 2001 Apr 2;20(7):1785-96
references.pmid: 11285241
references.citation: EMBO J. 1993 Dec;12(12):4715-26
references.pmid: 8223480
references.citation: Blood. 1996 May 1;87(9):3934-41
references.pmid: 8611723
references.citation: Trends Immunol. 2012 Jul;33(7):357-63
references.pmid: 22349458
references.citation: Genes Dev. 1999 Feb 15;13(4):462-71
references.pmid: 10049361
references.citation: Mol Aspects Med. 2009 Aug;30(4):191-296
references.pmid: 19371762
references.citation: Exp Cell Res. 2007 May 1;313(8):1518-32
references.pmid: 17391668
references.citation: J Biol Chem. 2006 May 5;281(18):12468-74
references.pmid: 16537540
references.citation: Cell Death Differ. 2008 Dec;15(12):1815-23
references.pmid: 18806759
references.citation: J Biol Chem. 2005 Apr 8;280(14):14302-9
references.pmid: 15684423
references.citation: Mol Biol Cell. 2008 Apr;19(4):1706-16
references.pmid: 18256291
references.citation: Cancer Res. 2008 Feb 1;68(3):657-63
references.pmid: 18245464
references.citation: New Phytol. 2010 Jan;185(1):83-9
references.pmid: 19863731
references.citation: Genome Biol. 2009;10(10):242
references.pmid: 19857271
references.citation: J Biol Chem. 1993 Jul 15;268(20):15185-92
references.pmid: 7686911
references.citation: EMBO J. 2011 Feb 2;30(3):510-23
references.pmid: 21157427
references.citation: Prog Mol Subcell Biol. 2003;31:153-85
references.pmid: 12494766
references.citation: Nature. 2007 Apr 19;446(7138):926-9
references.pmid: 17361132
references.citation: Mol Cell. 2001 Dec;8(6):1351-61
references.pmid: 11779509
references.citation: Endocrinology. 2009 May;150(5):2087-97
references.pmid: 19116344
references.citation: Gene. 1997 Dec 19;204(1-2):243-9
references.pmid: 9434190
references.citation: Oncogene. 2004 Jan 29;23(4):920-7
references.pmid: 14647452
references.citation: Biochim Biophys Acta. 2009 Jan;1792(1):14-26
references.pmid: 18992329
references.citation: EMBO J. 1993 Dec;12(12):4727-37
references.pmid: 8223481
references.citation: J Biol Chem. 2008 Jan 18;283(3):1223-7
references.pmid: 18024427
references.citation: Biochimie. 2011 Nov;93(11):1955-61
references.pmid: 21784124
references.citation: Oncogene. 2010 May 13;29(19):2807-16
references.pmid: 20190819
references.citation: J Biol Chem. 2004 Jun 4;279(23):24246-54
references.pmid: 15010457
references.citation: Blood. 2011 Mar 3;117(9):2708-17
references.pmid: 21127173
references.citation: Mol Cell. 2005 Nov 11;20(3):413-25
references.pmid: 16285923
references.citation: Blood Cells Mol Dis. 2010 Dec 15;45(4):284-8
references.pmid: 20863723
references.citation: Proc Natl Acad Sci U S A. 1971 Feb;68(2):378-82
references.pmid: 5277089
references.citation: Genes Dev. 2000 Dec 15;14(24):3166-78
references.pmid: 11124808
references.citation: Nature. 1994 Mar 10;368(6467):119-24
references.pmid: 8139654
references.citation: Mol Cell. 2009 Jul 10;35(1):1-10
references.pmid: 19595711
references.citation: Int J Biochem Cell Biol. 2007;39(11):2031-48
references.pmid: 17507279
references.citation: Proc Natl Acad Sci U S A. 1999 Aug 31;96(18):10403-8
references.pmid: 10468620
references.citation: Blood. 2012 May 31;119(22):5265-75
references.pmid: 22427201
references.citation: Nature. 2011 Sep 11;478(7367):64-9
references.pmid: 21909114
references.citation: FEBS J. 2011 Sep;278(18):3246-55
references.pmid: 21794093
references.citation: Biochem Soc Trans. 2010 Aug;38(4):1116-21
references.pmid: 20659014
references.citation: J Biol Chem. 1996 Nov 1;271(44):27299-303
references.pmid: 8910305
references.citation: Blood. 2010 Jul 8;116(1):85-96
references.pmid: 20410505
references.citation: J Cell Biol. 1990 Dec;111(6 Pt 1):2217-23
references.pmid: 1703534
references.citation: Genomics. 1997 Jul 15;43(2):165-70
references.pmid: 9244433
references.citation: Cell Res. 2008 Aug;18(8):834-45
references.pmid: 18560381
references.citation: Blood. 2012 May 10;119(19):4480-5
references.pmid: 22431577
references.citation: J Virol. 2004 Jun;78(12):6517-26
references.pmid: 15163745
references.citation: EMBO J. 1995 Sep 1;14(17):4336-49
references.pmid: 7556075
references.citation: Mol Cell. 2010 Sep 24;39(6):925-38
references.pmid: 20797886
references.citation: Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):52-7
references.pmid: 19966288
references.citation: J Immunol. 2000 Jun 15;164(12):6147-57
references.pmid: 10843664
references.citation: Nat Struct Mol Biol. 2005 Dec;12(12):1037-44
references.pmid: 16299516
references.citation: Prog Mol Subcell Biol. 2006;44:65-87
references.pmid: 17076265
references.citation: Mol Cell Biol. 1999 Nov;19(11):7347-56
references.pmid: 10523623
references.citation: J Biol Chem. 2006 Dec 1;281(48):37159-74
references.pmid: 16990281
references.citation: Blood. 2005 Mar 1;105(5):2146-53
references.pmid: 15522963
references.citation: Genes Dev. 2010 Jun 1;24(11):1073-4
references.pmid: 20516191
references.citation: Mol Cell Biol. 2012 Jan;32(2):513-26
references.pmid: 22083953
references.citation: Proc Natl Acad Sci U S A. 1997 Apr 15;94(8):3596-601
references.pmid: 9108022
references.citation: FEBS J. 2011 Feb;278(4):587-97
references.pmid: 21205204
references.citation: Adv Exp Med Biol. 2007;623:107-22
references.pmid: 18380343
references.citation: J Biol Chem. 2001 Jun 22;276(25):22648-54
references.pmid: 11283022