Predicted to enable calcium ion binding activity and cysteine-type deubiquitinase activity. Predicted to be involved in protein deubiquitination. Is an ortholog of C. elegans T24B8.7; K02C4.3; and C34F6.9. In C. elegans, cyk-3 is involved in several processes, including intracellular water homeostasis; mitotic cleavage furrow formation; and positive regulation of TORC1 signaling.