HO-TAG

The HO-TAG (homo-oligomeric tag) module comprises two multivalent coiled coil arrays (tetra- and hexavalent) each fused to a specific interaction domain. Combined expression of these arrays drives condensate formation.

By choosing the specific interaction domain pair, one can engineer this system as a sensor. For example, using a phospho-dependent interaction pair creates a live-cell sensor that can report on signaling cascade activation. The use of other interaction domain pairs allows as well for induction via small molecules.

PROS:
+ orthogonal molecular grammar
+ highly customizable for sensing specific signaling outputs (i.e., post-translational modifications)

CONS:
- two-component system