title: Characterization of a novel posttranslational modification in polypyrimidine tract-binding proteins by SUMO1.
abstract: Polypyrimidine tract-binding protein 1 (PTBP1) and its brainspecific homologue, PTBP2, are associated with pre-mRNAs and influence pre-mRNA processing, as well as mRNA metabolism and transport. They play important roles in neural differentiation and glioma development. In our study, we detected the expression of the two proteins in glioma cells and predicted that they may be sumoylated using SUMOplot analyses. We confirmed that PTBP1 and PTBP2 can be modified by SUMO1 with co-immunoprecipitation experiments using 293ET cells transiently co-expressing SUMO1 and either PTBP1 or PTBP2. We also found that SUMO1 modification of PTBP2 was enhanced by Ubc9 (E2). The mutation of the sumoylation site (Lys137) of PTBP2 markedly inhibited its modification by SUMO1. Interestingly, in T98G glioma cells, the level of sumoylated PTBP2 was reduced compared to that of normal brain cells. Overall, this study shows that PTBP2 is posttranslationally modified by SUMO1.
authors.affiliation: The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.affiliation: The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.affiliation: The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yin
authors.affiliation: The State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China.
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Peng
mesh_terms: D057809:HEK293 Cells; D006801:Humans; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D038941:Polypyrimidine Tract-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D025842:SUMO-1 Protein / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D009419:Nerve Tissue Proteins; C504334:PTBP2 protein, human; D025842:SUMO-1 Protein; C495501:SUMO1 protein, human; D038941:Polypyrimidine Tract-Binding Protein