Dataset Information

Transformation by Tribbles homolog 2 (Trib2) requires both the Trib2 kinase domain and COP1 binding.

ABSTRACT: Tribbles homolog 2 (Trib2) is a pseudokinase that induces acute myelogenous leukemia (AML) in mice and is highly expressed in a subset of human AML. Trib2 has 3 distinct regions, a proline-rich N-terminus, a serine/threonine kinase homology domain, and a C-terminal constitutive photomorphogenesis 1 (COP1)-binding domain. We performed a structure-function analysis of Trib2 using in vitro and in vivo assays. The N-terminus was not required for Trib2-induced AML. Deletion or mutation of the COP1-binding site abrogated the ability of Trib2 to degrade CCAAT/enhancer-binding protein-? (C/EBP-?), block granulocytic differentiation, and to induce AML in vivo. Furthermore, COP1 knockdown inhibited the ability of Trib2 to degrade C/EBP-?, showing that it is important for mediating Trib2 activity. We also show that the Trib2 kinase domain is essential for its function. Trib2 contains variant catalytic loop sequences, compared with conventional kinases, that we show are necessary for Trib2 activity. The kinase domain mutants bind, but cannot efficiently degrade, C/EBP-?. Together, our data demonstrate that Trib2 can bind both COP1 and C/EBP-?, leading to degradation of C/EBP-?. Identification of the functional regions of Trib2 that are essential to its oncogenic role provides the basis for developing inhibitors that will block Trib functions in cancer.

SUBMITTER: Keeshan K

PROVIDER: S-EPMC3012589 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Transformation by Tribbles homolog 2 (Trib2) requires both the Trib2 kinase domain and COP1 binding.

Keeshan Karen K Bailis Will W Dedhia Priya H PH Vega Maria E ME Shestova Olga O Xu Lanwei L Toscano Kristin K Uljon Sacha N SN Blacklow Stephen C SC Pear Warren S WS

Blood 20100830 23

Tribbles homolog 2 (Trib2) is a pseudokinase that induces acute myelogenous leukemia (AML) in mice and is highly expressed in a subset of human AML. Trib2 has 3 distinct regions, a proline-rich N-terminus, a serine/threonine kinase homology domain, and a C-terminal constitutive photomorphogenesis 1 (COP1)-binding domain. We performed a structure-function analysis of Trib2 using in vitro and in vivo assays. The N-terminus was not required for Trib2-induced AML. Deletion or mutation of the COP1-bi ...[more]

PMID: 20805362

Similar Datasets

Project description:Members of the Tribbles (TRIB) family of pseudokinases are critical components of intracellular signal transduction pathways in physiological and pathological processes. TRIBs, including TRIB2, have been previously shown as signaling mediators and scaffolding proteins regulating numerous cellular events such as proliferation, differentiation and cell death through protein stability and activity. However, the signaling network associated with TRIB2 and its binding partners in granulosa cells during ovarian follicular development is not fully defined. We previously reported that TRIB2 is differentially expressed in growing dominant follicles while downregulated in ovulatory follicles following the luteinizing hormone (LH) surge or human chorionic gonadotropin (hCG) injection. In the present study, we used the yeast two-hybrid screening system and in vitro coimmunoprecipitation assays to identify and confirm TRIB2 interactions in granulosa cells (GCs) of dominant ovarian follicles (DFs), which yielded individual candidate binding partners including calmodulin 1 (CALM1), inhibin subunit beta A (INHBA), inositol polyphosphate phosphatase-like 1 (INPPL1), 5'-nucleotidase ecto (NT5E), stearoyl-CoA desaturase (SCD), succinate dehydrogenase complex iron sulfur subunit B (SDHB) and Ras-associated protein 14 (RAB14). Further analyses showed that all TRIB2 binding partners are expressed in GCs of dominant follicles but are differentially regulated throughout the different stages of follicular development. CRISPR/Cas9-driven inhibition along with pQE-driven overexpression of TRIB2 showed that TRIB2 differently regulates expression of binding partners, which reveals the importance of TRIB2 in the control of gene expression linked to various biological processes such as proliferation, differentiation, cell migration, apoptosis, calcium signaling and metabolism. These data provide a larger view of potential TRIB2-regulated signal transduction pathways in GCs and provide strong evidence that TRIB2 may act as a regulator of target genes during ovarian follicular development.

Dataset Information

Transformation by Tribbles homolog 2 (Trib2) requires both the Trib2 kinase domain and COP1 binding.

Publications

Transformation by Tribbles homolog 2 (Trib2) requires both the Trib2 kinase domain and COP1 binding.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets