The present invention relates to novel agents that are useful for controlling sumoylation. In particular, the present invention relates to a sumoylation control agent comprising: (i) a pharmaceutically-effective amount of a HLS-5 polypeptide, isoform thereof, functional fragment thereof, or pharmaceutical composition thereof or (ii) a compound or composition capable of modulating the endogenous levels of HLS-5 or its activity or (iii) combinations thereof.
