Hair follicle (IMAGE) Rockefeller University Caption When researchers knocked out the RXRa receptor in a hair follicle, stem cells (green) were unable to engulf dying cells and debris (orange), leading to a buildup of waste that even the professional phagocytes (purple) were unable to fully remove. Credit Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development at The Rockefeller University Usage Restrictions Image may only be used to illustrate research described in the accompanying release. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.