Figure 4.

Models for TRIP13 regulation of diverse HORMA proteins. Substrate Specific Models (1): Substrate specificity is enforced by unique adaptors for each HORMA protein; (2): Substrate specificity is enforced by post-translational modification of the appropriate substrate. Substrate Nonspecific Models (3): Each HORMA protein competes for a limited supply of TRIP13-p31. High levels of DNA damage would thereby inhibit anaphase progression through TRIP13-p31 sequestration. C-REV7 indicates closed REV7; (4): TRIP13 acts on all substrates during a specific cell cycle phase or phases. TRIP13 is known to be active in mitosis and may represent another mechanism to suppress DNA repair in mitosis.