Comprehensive Profiling of Mammalian Tribbles Interactomes Implicates TRIB3 in Gene Repression

Abstract

The three human Tribbles (TRIB) pseudokinases have been implicated in a plethora of signaling and metabolic processes linked to cancer initiation and progression and can potentially be used as biomarkers of disease and prognosis. While their modes of action reported so far center around protein–protein interactions, the comprehensive profiling of TRIB interactomes has not been reported yet. Here, we have developed a robust mass spectrometry (MS)-based proteomics approach to characterize Tribbles’ interactomes and report a comprehensive assessment and comparison of the TRIB1, -2 and -3 interactomes, as well as domain-specific interactions for TRIB3. Interestingly, TRIB3, which is predominantly localized in the nucleus, interacts with multiple transcriptional regulators, including proteins involved in gene repression. Indeed, we found that TRIB3 repressed gene transcription when tethered to DNA in breast cancer cells. Taken together, our comprehensive proteomic assessment reveals previously unknown interacting partners and functions of Tribbles proteins that expand our understanding of this family of proteins. In addition, our findings show that MS-based proteomics provides a powerful tool to unravel novel pseudokinase biology.

Transcriptomic Analyses Reveal the Effects of Walnut Kernel Cake on Adipose Deposition in Pig

“…ETV4 may play a role in regulating of adipocyte differentiation and metabolism [36,37]. TRIB3 is involved in regulating cell proliferation, differentiation and apoptosis [38]. In adipocytes, TRIB3 may interact with the insulin signaling pathway to affect fat metabolism and insulin sensitivity [39].…”

The Pseudokinase TRIB1 in Immune Cells and Associated Disorders

“…As an example, the use of berberine has recently been shown to enhance Trib1 expression and reduce diabetic nephropathy in a mouse model [ 22 ]. However, depending on expressing cells and binding partners, TRIB1 functions were found to be variable and further comprehension is needed, notably comparing TRIB1 interactome and functions between cell types [ 76 ]. Studies highlighting TRIB1 structural conformation and binding partners are providing insights that would help to design high affinity small molecules able to prevent or modulate TRIB1 interactions [ 19 ].…”

“…As mentioned earlier, TRIB1 functions depend on interacting partners and may explain some of its cell-specific roles. Recently, a characterization of TRIB1 interactome has been performed by affinity purification mass spectrometry (AP-MS) in human embryonic kidney HEK293T and breast cancer MCF7 cell lines, exhibiting known interactors, such as COP1, and new interactors [ 76 ]. Interestingly, TRIB1 was found to interact with itself, suggesting homodimerization as well as heterodimerization with TRIB2.…”

“…Even with the same cell lines, different subcellular localizations were observed suggesting that cellular environment impacts TRIB1 localization. For example, while TRIB1 was found equally distributed between the nuclear and cytosolic fractions by Western blot in MCF7 and BT474 breast cancer cell lines [ 90 ], TRIB1 was mainly found in the cytoplasm of MCF7 cells in a recent report using confocal microscopy [ 76 ].…”

Pseudokinases, Tribbles Proteins and Cancer

“…Consistent with previous findings that TRIB2 acts as a repressor of FOXO3 protein, these two compounds induce the activity of the FOXO3 transcription factor and revert TRIB2mediated drug resistance. Hernández-Quiles et al conducted a comprehensive analysis of the interactomes of mammalian Tribbles proteins, shedding light on their molecular interactions and functional roles [7]. Their findings reveal that TRIB3, a member of the Tribbles family, plays a significant role in gene repression.…”