Eui Tae Kim; Young-Eui Kim; Ye Ji Kim; Myoung Kyu Lee; Gary S. Hayward; Jin-Hyun Ahn

“ Covalent modification of proteins by SUMO (SUMOylation) affects their activity, intracellular localization, stability, and interaction with other proteins and DNA. The cellular SUMOylation pathway, which is largely analogous to the ubiquitin modification pathway, regulates many important cellular processes [1] , [2] . ”

“ These findings suggested that IE1 SUMOylation may be detrimental for viruses trying to evade cellular innate immune responses, although the overall effect of IE1 SUMOylation on viral replication could be different. In this regard, IE2, by inhibiting IE1 SUMOylation, may assist in immune escape by the virus. The interplay between SUMOylation of two viral proteins has been shown in Epstein-Barr virus. The SIM-containing BGLF4 protein inhibits BZLF1 SUMOylation through its SUMO-binding activity and also reduces overall SUMOylation, which enhances EBV lytic infection [50] , [51] . ”

“ IE1 disrupts PML nuclear bodies (NBs) , also known as nuclear domain 10 (ND10) [23] – [24] . This activity correlates with the loss of SUMOylated PML NB components, such as PML and Sp100, which repress incoming viral genomes [25] – [26] . IE1 also interferes with type I interferon (IFN) signaling by directly targeting STAT2 using its near C-terminal region, and, to a lesser extent, by binding to STAT1 [27] – [28] . IE1 is modified by SUMO at K450 within the acidic domain [29] , [30] . ”

“ Cells extracts were clarified in a microcentrifuge and 30 μl of extracts were incubated with 350 μl of reaction buffer A (25 mM glycyl-glycine [pH 7.8] , 15 mM ATP, and 4 mM EGTA) and then mixed with 100 μl of 0.25 mM luciferin (Sigma-Aldrich) in reaction buffer A. A TD-20/20 luminometer (Turner Designs) was used for a 10-s assay of the photons produced (measured in relative light units) . ”

“ E. coli that had been transformed with the reaction products (pENTR clones) were selected, and the DNA inserts were analyzed by digestion with BsrGI and sequencing. Yeast cells expressing plasmids encoding GAL4-activation domain (AD) -ORF fusions were produced by transferring the ORFs from pENTR vectors to a pACTII [15] -based destination vector using LR Clonase. ”

“ Hahn, G & Stamminger, T (2009) , Importance of covalent and noncovalent SUMO interactions with the major human cytomegalovirus transactivator IE2p86 for viral infection, vol. 83, pp. 12881–12894, 19812159 BerndtAHofmann-WinklerHTavalaiNHahnGStammingerT, pmid:19812159 1 2 Lee, HR & Ahn, JH (2004) , Sumoylation of the major immediate-early IE2 protein of human cytomegalovirus Towne strain is not required for virus growth in cultured human fibroblasts, vol. ”

“ Passafaro, A & Chiocca, S (2007) , Targeting SUMO E1 to ubiquitin ligases: a viral strategy to counteract sumoylation, vol. 282, pp. 15376–15382, 17392274 BoggioRPassafaroAChioccaS, pmid:17392274 ↑ Heaton, PR; Deyrieux, AF; Bian, XL & Wilson, VG (2011) , HPV E6 proteins target Ubc9, the SUMO conjugating enzyme, vol. ”

“ Matunis, MJ & Hayward, GS, “Evaluation of interactions of human cytomegalovirus immediate-early IE2 regulatory protein with small ubiquitin-like modifiers and their conjugation enzyme Ubc9”, J Virol 75: 3859–3872, [ [pmid:11264375 AhnJHXuYJangWJMatunisMJHaywardGS] ] ↑ Barrasa, MI ”