title: Functional conservation of 14-3-3 isoforms in inhibiting bad-induced apoptosis.
abstract: 14-3-3 proteins are a family of homologous eukaryotic molecules with seven distinct isoforms in mammalian cells. Isoforms of 14-3-3 proteins interact with diverse ligands and are involved in the regulation of mitogenesis, cell cycle progression, and apoptosis. However, whether different 14-3-3 isoforms are responsible for distinct functions remains elusive. Here we report that multiple isoforms of 14-3-3 proteins were capable of binding to several ligands, Bad, Raf-1, and Cbl. In a functional assay of 14-3-3 isoforms, all mammalian 14-3-3 isoforms could inhibit Bad-induced apoptosis. Thus, 14-3-3 function in regulating one of its ligands, Bad, is conserved among mammalian isoforms. We addressed whether 14-3-3 isoforms are differentially expressed in tissues, which may in part determine isoform-specific interactions. In situ hybridization revealed that 14-3-3zeta was present in most tissues tested, but sigma was preferentially expressed in epithelial cells. Thus, isoforms of 14-3-3 can interact and control the function of selected protein ligands, and differential tissue distribution of 14-3-3 isoforms may contribute to their specific interactions and subsequent downstream signaling events.
authors.affiliation: Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Subramanian
authors.forename: S C
authors.initials: SC
authors.lastname: Masters
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: H
authors.initials: H
authors.lastname: Fu
mesh_terms: D048948:14-3-3 Proteins; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D053938:DNA Fragmentation; D005434:Flow Cytometry; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D014446:Tyrosine 3-Monooxygenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051025:bcl-Associated Death Protein
chemical_list: D048948:14-3-3 Proteins; C494819:BAD protein, human; C494820:Bad protein, mouse; D002352:Carrier Proteins; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D051025:bcl-Associated Death Protein; D014446:Tyrosine 3-Monooxygenase; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019908:Proto-Oncogene Proteins c-raf