Fluorescent separase activity sensor

A biosensor for measuring and/or detecting separase activity in cultured cells, comprising:

• a first fluorescent substance at a first end of the fragment of human Scc1, said fragment consisting of the polypeptide of SEQ ID NO. 1;
• a second fluorescent substance at the second end of the fragment consisting of the polypeptide of SEQ ID NO. 1:
• and
• a localization-targeting sequence for localizing the biosensor at a localization site within the cultured cells, said localization-targeting sequence at the N- or C-terminus of the biosensor:
• wherein the localization-targeting sequence is not a sequence derived from Scc1;
• wherein the first fluorescent substance and the second fluorescent substance have non-overlapping emission wavelengths that do not cause excitation of each other;
• and
• wherein the biosensor is a separase sensor configured to detect and/or measure separase activity at the localization site within the cultured cells as a function of a change in emission fluorescence of the biosensor resulting from cleavage of the fragment consisting of the polypeptide of SEQ ID NO. 1 by separase.