IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SUMO conjugation to spliceosomal proteins modulates spliceosome assembly and function
Autor/es:
POZZI, BERTA; BRAGADO, LAUREANO; MAMMI, PABLO; RISSO, GUILLERMO; SREBROW, ANABELLA
Lugar:
Mar del Plata
Reunión:
Congreso; Reunion Anual de la Sociedad Argentina de Investigacion en Bioquimica y Biología Molecular; 2015
Institución organizadora:
Sociedad Argentina de Investigacion en Bioquímicas y Biología Molecular (SAIB)
Resumen:
Since previous work from our laboratory has revealed the splicing factor SRSF1 as a regulator of the SUMO conjugation pathway, we started to explore a possible link between SUMO and the splicing process, focusing on the spliceosome, the multimegadalton ribonucleoprotein machine responsible for it. We found that the addition of recombinant SUMO-conjugating enzyme to an in vitro splicing reaction accelerates the appearance of mature mRNA while a SUMO protease retards it. By Mass Spec analysis of anti-SUMO immunoprecipitated proteins obtained from pre-mRNA-bound complexes at different steps of the splicing reaction, we identify several spliceosomal SUMO substrates, such as Prp3, Prp28 and Snu114, which we have validated in cultured cells. After identifying SUMO attachment sites in Prp3, we obtained a SUMOylation mutant (Prp3 K289,559R) that fails to increase splicing efficiency when overexpressed, and is unable to co-precipitate U2 and U5 snRNA as well as the spliceosomal proteins SF3a and Snu114, compared to the wt version. We are currently validating the hypothesis that the Prp3 SUMOylation mutant is unable to achieve similar splicing efficiency levels to the wt protein due to its diminished recruitment to active spliceosomes. We propose that SUMO conjugation to spliceosomal proteins could play a role in splicing dynamics by modulating protein-protein and/or protein-RNA interactions.