Columbia University Medical Center researchers have identified a molecular pathway responsible for the retention and release of the brain’s stem cells. This latest research builds on previous studies which demonstrated that stem cells live in specialized niches, or microenvironments, that support and maintain them. Neural stem cells (NSCs) in the stem cell niche are carefully regulated so that there are enough cells released to populate specific areas of the brain. Studies in mice have revealed that Id (inhibitor of differentiation) proteins directly regulate the production of a protein called Rap1GAP, which controls Rap1, a master regulator of cell adhesion. Scientists have discovered that this pathway is critical for the adhesion of NSCs to their niche as well as NSC maintenance. “Since cancer stem cells are difficult to treat, identifying these pathways may lead to more effective therapies for malignant brain tumors,” Anna Lasorella, who led the research with Antonio Lavarone, said.