About Notch and Delta signalling
This is probably a stupid or a wierd question. But I have never worked in cell signalling field so I need to know if there is an answer for this. It is about the Notch-Delta pathway in lateral inhibition during embryo development.
I was studying to my MSc application exam using The Molecular Biology of The Cell textbook. In chapter 15, the textbook describes the molecular mechanisms behind the lateral inhibition mediated by Notch receptors and Delta ligands.
Both Notch and Delta are transmembrane proteins that interacts with each other in a contact-dependent manner between adjacents cells. They are very important, for example, in epithelial precursor cell differentiation, when it determines if they are going to differentiate in a neural cell or a epithelial cell. After their interaction, Notch receptors are cleaved by proteases in the extracellular space and inside the membrane. This means that the Notch receptors are just used once after their activation. After the last cleavage, the cytoplasmatic tail is translocated to the nucleus where it interacts with a DNA-binding protein, creating a transcription activation complex and inducing the transcription of a set of genes.
In chapter 21 in the same textbook, is also written that lateral inhibition occurs both by the adjacent cells, creating an inhibition balance between them. Therefore, cells can determine their cell type fate by breaking this balance. However, I was thinking about this mechanisms and I have a question.
Considering that Notch receptors are just used once, eventually the number of receptors decrease as the lateral inhibition occurs. I believe it is reasonable to say that the cell which loses more receptors are bound to "lose this competition" that decides which cell type will be differentiated. In contrast, early development is a set of processes occurring spacially and temporally in a highly regulated manner where a cellular mechanism can be delayed until the time is right. So my question is:
Is there a known strategy used by the cell to maintain this balance between Notch and Delta for longer periods of time or the lateral inhibition is just a "fast competition" between cells to decide their fate?