SUMO-1 modification required for transformation by adenovirus type 5 early region 1B 55-kDa oncoprotein.
SUMO-1 is a small ubiquitin-related modifier protein that is covalently linked to many cellular and viral protein targets. Modification by SUMO-1 is proposed to play a role in protein targeting and/or stability. We show here that adenovirus type 5 early region 1B 55-kDa (E1B-55kDa) oncoprotein can be covalently modified by SUMO-1 in vivo through a major attachment site comprising a single lysine residue at amino acid position 104. The sequence surrounding this lysine matches the proposed PsiKxE consensus motif required for SUMO-1 conjugation. A single mutation (K104R) that abolishes SUMOylation of E1B-55kDa dramatically reduces the ability of the adenovirus type 5 protein to transform primary baby rat kidney cells in cooperation with E1A and to inhibit p53-mediated transactivation. Overexpression of SUMO-1 in adenovirus type 5 E1A/E1B-55kDa-transformed baby rat kidney cells causes the relocalization of E1B-55kDa from the cytoplasm to the nucleus, where it accumulates with SUMO-1 in dot- or track-like structures. Significantly, when SUMO-1 is ectopically expressed in transformed rat cells no effect on the cytoplasmic localization of the E1B-K104R mutant protein is observed. Our results demonstrate that SUMO-1 modification is required for transformation by adenovirus type 5 E1B-55kDa and provide further evidence for the idea that this posttranslational modification plays a role in protein targeting to specific subcellular sites.
Endter
C
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Institut für Medizinische Mikrobiologie und Hygiene, Universität Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany.
Kzhyshkowska
J
J
Stauber
R
R
Dobner
T
T
D000256:Adenoviridae / Q000235:genetics*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D002472:Cell Transformation, Viral; D003227:Conjugation, Genetic; D016384:Consensus Sequence; D007668:Kidney; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D025842:SUMO-1 Protein / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D014764:Viral Proteins; C056461:terminal protein, adenovirus