title: 14-3-3 mediated regulation of the tumor suppressor protein, RASSF1A.
abstract: Death receptor-dependent apoptosis is an important mechanism of growth control. It has been demonstrated that Ras association domain family protein 1A (RASSF1A) is a tumor suppressor protein involved in death receptor-dependent apoptosis. However, it is unclear how RASSF1A-mediated cell death is initiated. We have now detailed 14-3-3 dependent regulation of RASSF1A-mediated cell death. We demonstrate that basal association of RASSF1A with 14-3-3 was lost following stimulation with tumor necrosis factor alpha (TNFalpha) or TNFalpha related apoptosis inducing ligand (TRAIL). Subsequent to the loss of 14-3-3 association, RASSF1A associated with modulator of apoptosis (MOAP-1) followed by death receptor association with either TNFalpha receptor 1 (TNF-R1) or TRAIL receptor 1 (TRAIL-R1). 14-3-3 association required basal phosphorylation by the serine/threonine kinase, glycogen synthase kinase 3beta (GSK-3beta), on serine 175, 178, and 179. Mutation of these critical serines resulted in the loss of 14-3-3 association and earlier recruitment of RASSF1A to MOAP-1, TNF-R1, and TRAIL-R1. Furthermore, stable cells containing a triple serine mutant of RASSF1A [serine (S) 175 to alanine (A) [S175A], S178A, and S179A] resulted in increased basal cell death, enhanced Annexin V staining and enhanced cleavage of poly (ADP-ribose) polymerase (PARP) following TNFalpha stimulation when compared to stable cells containing wild type RASSF1A. RASSF1A-mediated cell death is, therefore, tightly controlled by 14-3-3 association.
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2N8, Canada.
authors.forename: Haya Abu
authors.initials: HA
authors.lastname: Ghazaleh
authors.forename: Renfred S
authors.initials: RS
authors.lastname: Chow
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Choo
authors.forename: Diana
authors.initials: D
authors.lastname: Pham
authors.forename: Jamie D
authors.initials: JD
authors.lastname: Olesen
authors.forename: Russell X
authors.initials: RX
authors.lastname: Wong
authors.forename: Christina
authors.initials: C
authors.lastname: Onyskiw
authors.forename: Shairaz
authors.initials: S
authors.lastname: Baksh
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001665:Binding Sites; D016923:Cell Death; D045744:Cell Line, Tumor; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D053218:Receptors, Death Domain / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C428449:MOAP1 protein, human; D050505:Mutant Proteins; C411762:RASSF1 protein, human; D053218:Receptors, Death Domain; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D047888:Receptors, Tumor Necrosis Factor, Type I; D025521:Tumor Suppressor Proteins; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3