title: Caspase-3 cleavage of DUSP6/MKP3 at the interdomain region generates active MKP3 fragments that regulate ERK1/2 subcellular localization and function.
abstract: MAPK (MAP kinase) phosphatase 3 (DUSP6/MKP3) is a cytosolic MKP (MAPK phosphatase) that regulates negatively ERK1/2 downstream to growth factor or apoptotic signaling. Transcription of DUSP6 gene is activated through the ERK1/2 pathway, which constitutes a feedback regulatory loop of ERK1/2 activation. However, the regulation of the function of the DUSP6/MKP3 protein is poorly known. MKP3 possesses a linker region between its N-terminal MAPK-binding domain and its C-terminal catalytic domain, which is conserved in the related MKPs DUSP7/MKPX and DUSP9/MKP4. In MKP3, the interdomain linker region contains a secondary ERK1/2 binding motif and an active nuclear export sequence. Here, we report that MKP3 protein levels are decreased in cells upon apoptotic stimulation in a caspase-dependent manner, and we identify a novel MKP3 regulatory mechanism mediated by the pro-apoptotic protease caspase-3, which involves the MKP3 interdomain linker region. Active caspase-3 targeted the linker region of MKP3 at several residues, rendering N-terminal and C-terminal MKP3 fragments that contain specific arrangements of nuclear export sequence and ERK1/2 interaction motifs. MKP3 caspase-3-generated fragments displayed differential properties to regulate ERK1/2 nuclear/cytosolic localization and activity. Our results indicate that caspase-3 cleavage of MKP3 down-regulates MKP3 full length and renders active MKP3 fragments, which may participate in novel regulatory pathways controlling the subcellular localization and activation of ERK1/2 during apoptosis.
authors.affiliation: Centro de Investigación Príncipe Felipe, Valencia, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Cejudo-Marín
authors.forename: Céline
authors.initials: C
authors.lastname: Tárrega
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Nunes-Xavier
authors.forename: Rafael
authors.initials: R
authors.lastname: Pulido
mesh_terms: D021581:Active Transport, Cell Nucleus; D017209:Apoptosis; D001665:Binding Sites; D053148:Caspase 3 / Q000378:metabolism*; D054642:Dual Specificity Phosphatase 6 / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D017434:Protein Structure, Tertiary
chemical_list: D010446:Peptide Fragments; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C517035:DUSP6 protein, human; D054642:Dual Specificity Phosphatase 6; C505407:CASP3 protein, human; D053148:Caspase 3