Modification of Daxx by small ubiquitin-related modifier-1.
Small ubiquitin-related modifier-1 (SUMO-1) is a protein that is covalently modified to various cellular proteins and protects cells against both anti-Fas and TNF-induced cell death. Previously, we reported that the C-terminus of Daxx interacted with Ubc9, an E2 type SUMO-1 conjugating enzyme, as well as with SUMO-1. In BOSC23 cells expressing FLAG-Daxx together with HA-SUMO-1, 110 and 130kDa Daxx appeared and the 130kDa band bound to both anti-HA and anti-FLAG antibodies. This means that Daxx can be covalently modified by SUMO-1. Substitution of K630 and K631 abrogated the modification of Daxx by SUMO-1, implying that K630 and K631 were essential for sumoylation. Daxx (K630, 631A) and Daxx (K634, 636, 637A) in which the putative C-terminal nuclear localization signals (NLSs) were disrupted appeared in the nucleus, suggesting that the C-terminal NLS was not functional. Daxx (K630, 631A), the sumoylation defective mutant, was able to interact with PML and co-localized with PML in the PML oncogenic domains (PODs). Thus, our data show that sumoylation status of Daxx does not affect its presence in PODs.
Jang
Moon-Sun
MS
Research Center for Biomedicinal Resources and Division of Life Science, PaiChai University, 439-6 Doma-2-dong, Seo-gu, Daejon 302-735, Republic of Korea.
Ryu
Seung-Wook
SW
Kim
Eunhee
E
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D056970:Co-Repressor Proteins; D016384:Consensus Sequence; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D021381:Protein Transport; D025842:SUMO-1 Protein / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D056970:Co-Repressor Proteins; C106985:DAXX protein, human; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D025842:SUMO-1 Protein