Tight junctions (TJ) are the structure of scaffolding proteins separating the apical and baso-lateral domains in an epithelium.

I assume that during the growth of this epithelium, cells have to deform (this is very clear in a cyst) and the TJ has to move on the surface of the cells.

I'm wondering what is the mechanism that tells where exactly the TJ is going to be. I mean on the one hand I understand that cell-cell adhesion wants to make the surface of contact larger, but on the other hand I don't know what is the mechanism that makes the tight junction not being pushed and that let the apical domain not infinitely small.

Formulating it a bit differently : what is regulating the size of the cell-lumen surface ? Or the size of the lumen ?