The SGT1-specific (SGS) domain is a module of ~90 amino acids, which was initially identified in eukaryotic SGT1 proteins [1]. It was latter also found in calcyclin-binding proteins [2]. The SGS domain has been shown to bind to proteins of the S100 family, which are thought to function as sensors of calcium ion concentration in the cell [2].

Some proteins known to contain a SGS domain are listed below:

• Yeast suppressor of the G2 allele of skp1 (SGT1). It is required for cell cycle progression at the G1/S-phase and G2/M-phase transitions. It associates with Skp1 and regulates its function in the Skp1/Cullin1/F-box complex ubiquitin ligase and in kinetochore complexes.
• Arabidopsis thaliana SGT1a and SGT1b.
• Mammalian SGT1.
• Mammalian calcyclin-binding protein/Siah-1-interacting protein (CacyBP/SIP), a component of a novel pathway of β-catenin ubiquitination.

The profile we developed covers the entire SGS domain.