title: The death effector domain protein PEA-15 prevents nuclear entry of ERK2 by inhibiting required interactions.
abstract: ERK2 nuclear-cytoplasmic distribution is regulated in response to hormones and cellular state without the requirement for karyopherin-mediated nuclear import. One proposed mechanism for the movement of ERK2 into the nucleus is through a direct interaction between ERK2 and nucleoporins present in the nuclear pore complex. Previous reports have attributed regulation of ERK2 localization to proteins that activate or deactivate ERK2, such as the mitogen-activated protein (MAP) kinase kinase MEK1 and MAP kinase phosphatases. Recently, a small non-catalytic protein, PEA-15, has also been demonstrated to promote a cytoplasmic ERK2 localization. We found that the MAP kinase insert in ERK2 is required for its interaction with PEA-15. Consistent with its recognition of the MAP kinase insert, PEA-15 blocked activation of ERK2 by MEK1, which also requires the MAP kinase insert to interact productively with ERK2. To determine how PEA-15 influences the localization of ERK2, we used a permeabilized cell system to examine the effect of PEA-15 on the localization of ERK2 and mutants that have lost the ability to bind PEA-15. Wild type ERK2 was unable to enter the nucleus in the presence of an excess of PEA-15; however, ERK2 lacking the MAP kinase insert largely retained the ability to enter the nucleus. Binding assays demonstrated that PEA-15 interfered with the ability of ERK2 to bind to nucleoporins. These results suggest that PEA-15 sequesters ERK2 in the cytoplasm at least in part by interfering with its ability to interact with nucleoporins, presenting a potential paradigm for regulation of ERK2 localization.
authors.affiliation: Department of Pharmacology, the University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9041, USA.
authors.forename: Angelique W
authors.initials: AW
authors.lastname: Whitehurst
authors.forename: Fred L
authors.initials: FL
authors.lastname: Robinson
authors.forename: Mary Shannon
authors.initials: MS
authors.lastname: Moore
authors.forename: Melanie H
authors.initials: MH
authors.lastname: Cobb
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005656:Fungal Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D048369:MAP Kinase Kinase 1; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D020798:Two-Hybrid System Techniques
chemical_list: D051017:Apoptosis Regulatory Proteins; D005656:Fungal Proteins; D008164:Luminescent Proteins; D028861:Nuclear Pore Complex Proteins; C513083:Nup153 protein, rat; C490443:Pea15 protein, rat; D010750:Phosphoproteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases