Human TRIB2 oscillates during the cell cycle and promotes ubiquitination and degradation of CDC25C

Liang, K. L., Paredes, R., Carmody, R. , Eyers, P. A., Meyer, S., McCarthy, T. V. and Keeshan, K. (2016) Human TRIB2 oscillates during the cell cycle and promotes ubiquitination and degradation of CDC25C. International Journal of Molecular Sciences, 17(9), 1378. (doi: 10.3390/ijms17091378) (PMID:27563873) (PMCID:PMC5037658)

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Tribbles homolog 2 (TRIB2) is a member of the mammalian Tribbles family of serine/threonine pseudokinases (TRIB1-3). Studies of TRIB2 indicate that many of the molecular interactions between the single Drosophila Tribbles (Trbl) protein and interacting partners are evolutionary conserved. In this study, we examined the relationship between TRIB2 and cell division cycle 25 (CDC25) family of dual-specificity protein phosphatases (mammalian homologues of Drosophila String), which are key physiological cell cycle regulators. Using co-immunoprecipitation we demonstrate that TRIB2 interacts with CDC25B and CDC25C selectively. Forced overexpression of TRIB2 caused a marked decrease in total CDC25C protein levels. Following inhibition of the proteasome, CDC25C was stabilized in the nuclear compartment. This implicates TRIB2 as a regulator of nuclear CDC25C turnover. In complementary ubiquitination assays, we show that TRIB2-mediated degradation of CDC25C is associated with lysine-48-linked CDC25C polyubiquitination driven by the TRIB2 kinase-like domain. A cell cycle associated role for TRIB2 is further supported by the cell cycle regulated expression of TRIB2 protein levels. Our findings reveal mitotic CDC25C as a new target of TRIB2 that is degraded via the ubiquitin proteasome system. Inappropriate CDC25C regulation could mechanistically underlie TRIB2 mediated regulation of cellular proliferation in neoplastic cells.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Carmody, Dr Ruaidhri and Keeshan, Dr Karen
Authors: Liang, K. L., Paredes, R., Carmody, R., Eyers, P. A., Meyer, S., McCarthy, T. V., and Keeshan, K.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
College of Medical Veterinary and Life Sciences > School of Infection & Immunity
Journal Name:International Journal of Molecular Sciences
ISSN (Online):1422-0067
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in International Journal of Molecular Sciences 17(9):1378
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
623941Targeting Trib2 oncogenic signalling in normal and malignant stem cells.Karen KeeshanBloodwise (BLOODWIS)13011RI CANCER SCIENCES
671081Investigating NF-kB p50 phosphorylation and the regulation of transcriptionRuaidhri CarmodyMedical Research Council (MRC)MR/M010694/1III -IMMUNOLOGY
659831Dissecting the function of Bcl-3 in NF-kappaB signaling in B cellsRuaidhri CarmodyBiotechnology and Biological Sciences Research Council (BBSRC)BB/M003671/1RI INFECTION IMMUNITY & INFLAMMATION