A novel link between SUMO modification and cancer metastasis.

SUMO (small ubiquitin-related modifier), a member of ubiquitin-like proteins, modifies a large number of transcription factors and coregulators. Although ubiquitin and SUMO exhibit structural similarities, the biological output of SUMOylation is somewhat distinct from protein degradation that is mainly mediated by ubiquitination. SUMOylation is involved in the regulation of the subcellular localization and stabilization of transcriptional cofactors and chromatin remodeling factors. Given the number of oncogenes and tumor suppressor genes that have been defined as targets for SUMOylation, studies on protein SUMOylation may shed light on the mechanism of tumorigenesis and metastasis. New roles of SUMOylation of a chromatin-remodeling complex have been elucidated. The SUMOylation status of the reptin chromatin-remodeling complex modulates the KAI1 metastasis suppressor gene and the invasive activity of cancer cells with metastatic potential; this revealed a novel link between SUMO modification and cancer metastasis. Here I overview these findings and discuss biological importance of protein SUMOylation in cancer metastasis.