SUMO-1 promotes association of SNURF (RNF4) with PML nuclear bodies.
Small nuclear RING finger protein SNURF (RNF4) is involved in transcriptional and cell growth regulation. We show here that a significant portion of endogenous SNURF localizes to nuclear bodies (NBs) that overlap with or are adjacent to domains containing endogenous promyelocytic leukemia (PML) protein and small ubiquitin-like modifier-1 (SUMO-1). In biochemical assays, SNURF efficiently binds SUMO-1 in a noncovalent fashion. SNURF is also covalently modified by SUMO-1 at nonconsensus attachment sites. Ectopic expression of SUMO-1 markedly enhances the interaction between PML3 (PML IV) and SNURF, but covalent attachment of SUMO-1 to neither protein is required. Moreover, overexpression of PML3, but not PML-L (PML III), abolishes the coactivation function of SNURF in transactivation assays, which parallels the ability of PML3 to recruit SNURF to nuclear bodies. In sum, we have identified SNURF as a novel component in PML bodies and suggest that SUMO-1-facilitated sequestration into these nuclear domains regulates the transcriptional activity of SNURF.
Häkli
Marika
M
Biomedicum Helsinki, Institute of Biomedicine, University of Helsinki, P.O. Box 63, FI-00014 Helsinki, Finland.
Karvonen
Ulla
U
Jänne
Olli A
OA
Palvimo
Jorma J
JJ
D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D022003:Cell Nucleus Structures / Q000737:chemistry* / Q000648:ultrastructure; D005260:Female; D006367:HeLa Cells; D006801:Humans; D009363:Neoplasm Proteins / Q000032:analysis* / Q000378:metabolism; D009687:Nuclear Proteins / Q000032:analysis* / Q000378:metabolism; D000071156:Promyelocytic Leukemia Protein; D025842:SUMO-1 Protein / Q000502:physiology*; D014157:Transcription Factors / Q000032:analysis* / Q000378:metabolism; D025521:Tumor Suppressor Proteins
D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; C114070:RNF4 protein, human; C445239:SNURF protein, human; D025842:SUMO-1 Protein; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human