May play a role in ubiquitination and subsequent proteasomal degradation of target proteins. Probably associates with SCF (SKP1-CUL1-F-box protein) complex through interaction with SKP1. Interacts with S100A6. Interacts with HSP90. Translocates to the nucleus upon heat shock, requiring S100A6. The CS domain mediates interaction with HSP90. Phosphorylated at Ser-281 and Ser-331, dephosphorylation promotes nuclear translocation, most likely due to disruption of the SUGT1-HSP90 complex. Belongs to the SGT1 family.