title: Klotho Regulates 14-3-3ζ Monomerization and Binding to the ASK1 Signaling Complex in Response to Oxidative Stress.
abstract: The reactive oxygen species (ROS)-sensitive apoptosis signal-regulating kinase 1 (ASK1) signaling complex is a key regulator of p38 MAPK activity, a major modulator of stress-associated with aging disorders. We recently reported that the ratio of free ASK1 to the complex-bound ASK1 is significantly decreased in Klotho-responsive manner and that Klotho-deficient tissues have elevated levels of free ASK1 which coincides with increased oxidative stress. Here, we tested the hypothesis that: 1) covalent interactions exist among three identified proteins constituting the ASK1 signaling complex; 2) in normal unstressed cells the ASK1, 14-3-3ζ and thioredoxin (Trx) proteins simultaneously engage in a tripartite complex formation; 3) Klotho's stabilizing effect on the complex relied solely on 14-3-3ζ expression and its apparent phosphorylation and dimerization changes. To verify the hypothesis, we performed 14-3-3ζ siRNA knock-down experiments in conjunction with cell-based assays to measure ASK1-client protein interactions in the presence and absence of Klotho, and with or without an oxidant such as rotenone. Our results show that Klotho activity induces posttranslational modifications in the complex targeting 14-3-3ζ monomer/dimer changes to effectively protect against ASK1 oxidation and dissociation. This is the first observation implicating all three proteins constituting the ASK1 signaling complex in close proximity.
authors.affiliation: Centers for Proteomics and Systems Biology, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 1825 Pressler Street, Houston, Texas, 77030, United States of America; Division of Oncology, Department of Internal Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 6410 Fannin, UTPB Suite 722, Houston, Texas 77030 United States of America.
authors.forename: Reynolds K
authors.initials: RK
authors.lastname: Brobey
authors.affiliation: Centers for Proteomics and Systems Biology, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 1825 Pressler Street, Houston, Texas, 77030, United States of America; Companion Dx Reference Laboratory, LLC, 10301 Stella Link Rd., Suite C, Houston, Texas 77025, United States of America.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Dheghani
authors.affiliation: Centers for Proteomics and Systems Biology, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 1825 Pressler Street, Houston, Texas, 77030, United States of America; Department of NanoMedicine and Biomedical Engineering, The University of Texas Health Science Center at Houston (UTHealth), MD Anderson Cancer Center Bldg-3SCRB, 1881 East Road, Houston, Texas 77030, United States of America; Division of Pulmonary Medicine, Department of Internal Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 6431 Fannin, MSB 1.274, Houston, Texas 77030, United States of America.
authors.forename: Philip P
authors.initials: PP
authors.lastname: Foster
authors.affiliation: Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, JAPAN; Department of Pathology, Center for Mineral Metabolism, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9072, United States of America.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kuro-O
authors.affiliation: Centers for Proteomics and Systems Biology, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 1825 Pressler Street, Houston, Texas, 77030, United States of America; Companion Dx Reference Laboratory, LLC, 10301 Stella Link Rd., Suite C, Houston, Texas 77025, United States of America.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Rosenblatt
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D005966:Glucuronidase / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D000090265:Klotho Proteins; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism*; D018384:Oxidative Stress; D011485:Protein Binding; D055503:Protein Multimerization; D015398:Signal Transduction
chemical_list: D048948:14-3-3 Proteins; D048848:MAP Kinase Kinase Kinase 5; D005966:Glucuronidase; D000090265:Klotho Proteins