The S. pombe translation initiation factor eIF4G is sumoylated and associates with the SUMO protease Ulp2

Jongjitwimol, Jirapas, Feng, Min, Zhou, Lihong, Wilkinson, Oliver, Small, Lauren, Baldock, Robert, Taylor, Deborah L, Smith, Duncan, Bowler, Lucas, Morley, Simon J and Watts, Felicity (2014) The S. pombe translation initiation factor eIF4G is sumoylated and associates with the SUMO protease Ulp2. PLoS ONE, 9 (5). e94182. ISSN 1932-6203

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Abstract

SUMO is a small post-translational modifier, that is attached to lysine residues in target proteins. It acts by altering proteinprotein
interactions, protein localisation and protein activity. SUMO chains can also act as substrates for ubiquitination,
resulting in proteasome-mediated degradation of the target protein. SUMO is removed from target proteins by one of a
number of specific proteases. The processes of sumoylation and desumoylation have well documented roles in DNA
metabolism and in the maintenance of chromatin structure. To further analyse the role of this modification, we have
purified protein complexes containing the S. pombe SUMO protease, Ulp2. These complexes contain proteins required for
ribosome biogenesis, RNA stability and protein synthesis. Here we have focussed on two translation initiation factors that
we identified as co-purifying with Ulp2, eIF4G and eIF3h. We demonstrate that eIF4G, but not eIF3h, is sumoylated. This
modification is increased under conditions that produce cytoplasmic stress granules. Consistent with this we observe partial
co-localisation of eIF4G and SUMO in stressed cells. Using HeLa cells, we demonstrate that human eIF4GI is also sumoylated;
in vitro studies indicate that human eIF4GI is modified on K1368 and K1588, that are located in the C-terminal eIF4A- and
Mnk-binding sites respectively.

Item Type: Article
Schools and Departments: School of Life Sciences > Sussex Centre for Genome Damage and Stability
Subjects: Q Science > QD Chemistry > QD0241 Organic chemistry > QD0415 Biochemistry
Depositing User: Gee Wheatley
Date Deposited: 07 Aug 2014 11:05
Last Modified: 07 Mar 2017 06:33
URI: http://sro.sussex.ac.uk/id/eprint/49524

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