The unexpected localisation of p27 in the cortex

Known for its involvement in the regulation of the cell cycle, p27 is a small protein that allows stem cells to exit the cycle and give birth to differentiated cells, such as neurons. It inhibits enzymes from the family of cycline-dependent kinases (CDKs). It is expressed in different cell types and tissues of the human body. “We decided to study this protein because we were intrigued by its localisation in the developing cortex”, explains Laurent Nguyen. “At the beginning, we thought that p27 only played a role in controlling the cell cycle in stem cells and progenitor cells. But analyses of this protein’s distribution pattern in the brain showed that p27 was also located in neurons and, therefore, in post-mitotic cells,”, continues the scientist. “Among other things, our research revealed that p27 was expressed by migrating neurons in the cortex". In view of these observations, the researchers concluded that aside from cell cycle exit, p27 may play a role in neuronal maturation.

Taking their research one step further, Laurent Nguyen’s team was able to confirm this hypothesis. p27 does indeed control the migration of cortical interneurons thanks to  novel molecular domains that are not involve in cell cycle regulation.