In situ SUMOylation analysis reveals a modulatory role of RanBP2 in the nuclear rim and PML bodies

Journal Article · Mon May 01 04:00:00 EDT 2006 · Experimental Cell Research

DOI:https://doi.org/10.1016/j.yexcr.2006.01.013· OSTI ID:20775370

Saitoh, Noriko ^[1]; Uchimura, Yasuhiro ^[2]; Tachibana, Taro ^[3]; Sugahara, Satoko ^[3]; Saitoh, Hisato ^[2]; Nakao, Mitsuyoshi ^[2]

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1. Department of Regeneration Medicine, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811 (Japan) and 21st Century Center of Excellence, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811 (Japan)
2. Department of Regeneration Medicine, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811 (Japan)
3. Department of Bioengineering, Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan)

SUMO modification plays a critical role in a number of cellular functions including nucleocytoplasmic transport, gene expression, cell cycle and formation of subnuclear structures such as promyelocytic leukemia (PML) bodies. In order to identify the sites where SUMOylation takes place in the cell, we developed an in situ SUMOylation assay using a semi-intact cell system and subsequently combined it with siRNA-based knockdown of nucleoporin RanBP2, also known as Nup358, which is one of the known SUMO E3 proteins. With the in situ SUMOylation assay, we found that both nuclear rim and PML bodies, besides mitotic apparatuses, are major targets for active SUMOylation. The ability to analyze possible SUMO conjugation sites would be a valuable tool to investigate where SUMO E3-like activities and/or SUMO substrates exist in the cell. Specific knockdown of RanBP2 completely abolished SUMOylation along the nuclear rim and dislocated RanGAP1 from the nuclear pore complexes. Interestingly, the loss of RanBP2 markedly reduced the number of PML bodies, in contrast to other, normal-appearing nuclear compartments including the nuclear lamina, nucleolus and chromatin, suggesting a novel link between RanBP2 and PML bodies. SUMOylation facilitated by RanBP2 at the nuclear rim may be a key step for the formation of a particular subnuclear organization. Our data imply that SUMO E3 proteins like RanBP2 facilitate spatio-temporal SUMOylation for certain nuclear structure and function.

• OSTI ID: 20775370
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 8 Vol. 312; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CELL CYCLE
CHROMATIN
GENES
LEUKEMIA
PROTEINS
RESONANCE IONIZATION MASS SPECTROSCOPY
SUBSTRATES