The stem cells have a capacity of multidirectional differentiation. They can differentiate into different cells which own special functions. That`s why we call them “omnipotent”. How to achieve this shift(differentiation)? Is there a switch which can adjust this mechanism?
Then we come up with a hypothesis: There should exist a kind of “stem switch” during the differentiation, which can be affected by the cell themselves (such as cell density) and the surroundings. This magic switch can change the multidirectional cells into the particular function cells.
We are happy to know that this hypothesis is proved to be true recently----There really has a special switch to regulate differentiation.
Figure 1. Bistable mechanism of stem cell differentiation [1]
Reference
[1] Ben Scheres et al. A Bistable Circuit Involving SCARECROW-RETINOBLASTOMA Integrates Cues to Inform Asymmetric Stem Cell Division. CELL. Volume 150, Issue 5, 31 August 2012, Pages 1002–1015
"
