Lrig1: a new master regulator of epithelial stem cells
The intestine represents the most vigorously renewing, adult epithelial tissue that makes maintenance of its homeostasis a delicate balance between proliferation, cell cycle arrest, migration, differentiation, and cell death. These processes are precisely controlled by a network of developmental signalling cascades, which include Wnt, Notch, BMP/TGF beta, and Hedgehog pathways. A new, elegant study by Wong et al (2012) now adds Lrig1 as a key player in the control of intestinal homeostasis. As for epidermal stem cells, Lrig1 limits the size of the intestinal progenitor compartment by dampening EGF/ErbB-triggered stem cell expansion.