title: The p76(Rb) and p100(Rb) truncated forms of the Rb protein exert antagonistic roles on cell death regulation in human cell lines.
abstract: Several caspase-cleaved forms of the retinoblastoma protein have been described. Here, we compared the effect of full-length Rb versus the truncated p76(Rb) and p100(Rb) proteins on cell death regulation in five human cell lines. Interestingly, we observed that p76(Rb) triggers cell death in all tested cell lines and that p100(Rb) protects two cell lines against etoposide or TNF-alpha-induced cell death, whereas full-length Rb has no apoptotic effect. These results show that truncated forms of Rb can have specific activities in the regulation of cell death. They also suggest that caspase cleavage of Rb should not be simply assimilated to a degradation process. Finally, we show that cell death induced by p76(Rb) is Bax-dependent and is diminished by Bcl-2 overexpression or by caspase inhibition and that p100(Rb) could inhibit cell death by decreasing both p53 stability and caspase activity.
authors.affiliation: Université de Versailles/St Quentin-en-Yvelines, CNRS FRE3216, Laboratoire de génétique et biologie cellulaire/Ecole Pratique des Hautes Etudes, Laboratoire de génétique moléculaire et physiologique, 45 avenue des Etats-Unis, 78035 Versailles cedex, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Le Floch
authors.forename: Vincent
authors.initials: V
authors.lastname: Rincheval
authors.forename: Ioana
authors.initials: I
authors.lastname: Ferecatu
authors.forename: Rahamata
authors.initials: R
authors.lastname: Ali-Boina
authors.forename: Flore
authors.initials: F
authors.lastname: Renaud
authors.forename: Bernard
authors.initials: B
authors.lastname: Mignotte
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Vayssière
mesh_terms: D017209:Apoptosis; D020169:Caspases / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D055550:Protein Stability; D016160:Retinoblastoma Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000378:metabolism
chemical_list: D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D051025:bcl-Associated Death Protein; D020169:Caspases