Arabidopsis eIF3e is regulated by the COP9 signalosome and has an impact on development and protein translation

Yahalom, Avital; Kim, Tae‐Houn; Roy, Bijoyita; Singer, Ruth A.; Arnim, Albrecht G. von; Chamovitz, Daniel

doi:10.1111/j.1365-313x.2007.03347.x

Cited by 41 publications

(44 citation statements)

References 66 publications

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“…CRLs are activated by neddylation of their cullin subunits, a process regulated by the CSN complex [54,55]. Previous studies in yeast, humans and plants have shown that depletion of Int6 homologues affects both proteasome and CSN activity [16,56]. In contrast, studies in Drosophila revealed that Int6 is an essential gene required for cullin neddylation but not for proteasome function [19].…”

Section: Discussionmentioning

confidence: 99%

The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure

et al. 2017

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INT6/eIF3e is a highly conserved component of the translation initiation complex that interacts with both the 26S proteasome and the COP9 signalosome, two complexes implicated in ubiquitin-mediated protein degradation. The INT6 gene was originally identified as the insertion site of the mouse mammary tumor virus (MMTV), and later shown to be involved in human tumorigenesis. Here we show that depletion of the Drosophila orthologue of INT6 (Int6) results in short mitotic spindles and deformed centromeres and kinetochores with low intra-kinetochore distance. Poleward flux of microtubule subunits during metaphase is reduced, although fluorescence recovery after photobleaching (FRAP) demonstrates that microtubules remain dynamic both near the kinetochores and at spindle poles. Mitotic progression is delayed during metaphase due to the activity of the spindle assembly checkpoint (SAC). Interestingly, a deubiquitinated form of the kinesin Klp67A (a putative orthologue of human Kif18A) accumulates near the kinetochores in Int6-depleted cells. Consistent with this finding, Klp67A overexpression mimics the Int6 RNAi phenotype. Furthermore, simultaneous depletion of Int6 and Klp67A results in a phenotype identical to RNAi of just Klp67A, which indicates that Klp67A deficiency is epistatic over Int6 deficiency. We propose that Int6-mediated ubiquitination is required to control the activity of Klp67A. In the absence of this control, excess of Klp67A at the kinetochore suppresses microtubule plus-end polymerization, which in turn results in reduced microtubule flux, spindle shortening, and centromere/kinetochore deformation.

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Section: Discussionmentioning

confidence: 99%

The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure

et al. 2017

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“…Yahalom et al (2008) have suggested that a precise regulation of eIF3e (a subunit of eIF3) content is necessary for a normal development in Arabidopsis as an excess of eIF3e inhibits translation. This regulation of eIF3e content is mediated by COP9 signalosome.…”

Section: Roles Of Translation Initiation System In Plantsmentioning

confidence: 99%

“…In some cases the over-expression of desired eIF(s) may be required, whereas in other cases, inhibition or minimizing expression of eIF(s) might be desirable. For example, the over-expression of eIF3e has been shown to inhibit translation in Arabidopsis (Yahalom et al 2008). Similarly, an attempt of gene pyramiding for pathogen resistance using a combination of eIF4E1 and eIFiso4E has resulted in male gametophyte lethality (Callot and Gallois 2014).…”

Section: Conclusion and Future Perspectivementioning

confidence: 99%

Translation initiation in plants: roles and implications beyond protein synthesis

et al. 2015

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Protein synthesis is a ubiquitous and essential process in all organisms, including plants. It is primarily regulated at translation initiation stage which is mediated through a number of translation initiation factors (eIFs). It is now becoming more apparent that in addition to synthesis of proteins, eIFs also regulate various aspects of plant development and their interaction with environment. Translation initiation factors, such as eIF3, eIF4A, eIF4E, eIF4G, and eIF5A affect different processes during vegetative and reproductive growth like embryogenesis, xylogenesis, flowering, sporogenesis, pollen germination, etc. On the contrary, eIF1A, eIF2, eIF4, and eIF5A are associated with interaction of plants with different abiotic stresses, such as high temperature, salinity, oxidative stress, etc. Similarly, eIF4E and eIF4G have roles in interaction with many viruses. Therefore, the translation initiation factors are important candidates for improving plant performance and adaptation. A large number of genes encoding eIFs can functionally be validated and utilized through genetic engineering approaches for better adaptability and performance of plants by inhibiting/minimizing or increasing expression of desired eIF(s).

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“…complexes COP9/signalosome and eIF3 ( 126,127 ) . Thus, whether a dedicated chaperone(s) exists for the lid assembly is an open question.…”

Section: Assembly Pathway Of the 19s Lid Complexmentioning

confidence: 99%

Assembly and Function of the Proteasome

Saeki

Tanaka

2012

Methods in Molecular Biology

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Proteasome is a highly organized protease complex comprising a catalytic 20S core particle (CP) and two 19S regulatory particles (RP), which together form the 26S structure. The 26S proteasome is responsible for the degradation of most ubiquitylated proteins through a multistep process involving recognition of the polyubiquitin chain, unfolding of the substrate, and translocation of the substrate into the active site in the cavity of the CP. Recent studies have shed light on various aspects of the complex functions of the 26S proteasome. In addition, the recent identification of various proteasome-dedicated chaperones indicates that the assembly pathways of the RP and CP are multistep processes. In this review, we summarize recent advances in the understanding of the proteasome structure, function, and assembly.

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Arabidopsis eIF3e is regulated by the COP9 signalosome and has an impact on development and protein translation

Cited by 41 publications

References 66 publications

The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure

The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure

Translation initiation in plants: roles and implications beyond protein synthesis

Assembly and Function of the Proteasome

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