Caspase cleavage of Ets-1 p51 generates fragments with transcriptional dominant-negative function.
Ets-1 is a transcription factor that plays an important role in various physiological and pathological processes, such as development, angiogenesis, apoptosis and tumour invasion. In the present study, we have demonstrated that Ets-1 p51, but not the spliced variant Ets-1 p42, is processed in a caspase-dependent manner in Jurkat T-leukaemia cells undergoing apoptosis, resulting in three C-terminal fragments Cp20, Cp17 and Cp14 and a N-terminal fragment, Np36. In vitro cleavage of Ets-1 p51 by caspase 3 produces fragments consistent with those observed in cells undergoing apoptosis. These fragments are generated by cleavage at three sites located in the exon VII-encoded region of Ets-1 p51. This region is absent from the Ets-1 p42 isoform, which therefore cannot be cleaved by caspases. In Ets-1 p51, cleavage generates C-terminal fragments containing the DNA-binding domain, but lacking the transactivation domain. The Cp17 fragment, the major cleavage product generated during apoptosis, is devoid of transcriptional activity and inhibits Ets-1 p51-mediated transactivation of target genes by competing with Ets-1 p51 for binding to Ets-binding sites present in the target promoters. In the present study, we have demonstrated that caspase cleavage of Ets-1 within the exon VII-encoded region leads to specific down-regulation of the Ets-1 p51 isoform during apoptosis. Furthermore, our results establish that caspase cleavage generates a stable C-terminal fragment that acts as a natural dominant-negative form of the full-length Ets-1 p51 protein.
Choul-Li
Souhaila
S
CNRS UMR 8161, Institut de Biologie de Lille, Institut Pasteur de Lille, Université Lille Nord de France, IFR 142, B.P. 447, 1 rue Calmette, 59021 Lille Cedex, France.
Leroy
Catherine
C
Leprivier
Gabriel
G
Laitem
Clélia
C
Tulasne
David
D
Aumercier
Marc
M
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D050784:Proto-Oncogene Protein c-ets-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015533:Transcriptional Activation
C494041:ETS1 protein, human; D020033:Protein Isoforms; D050784:Proto-Oncogene Protein c-ets-1; D053148:Caspase 3