Antagonistic drivers share BuMPy pathway

Seemingly confounding and contradictory, the ability of bone morphogenetic proteins (BMPs) to promote both proliferation and terminal differentiation (and even apoptosis!) of neuronal stem cells—to both expand and limit precursor cell numbers—now makes perfectly good sense. At least it does in light of the conclusions drawn by Ronald McKay, David Panchision, and colleagues (National Institutes of Health, Bethesda, MD), who postulate a mechanism by which BMP ligands control both the production and fate of neural precursor cells.

Panchision attributes this “dynamic process” to the sequential and linked expression and function of two BMP receptors, BMPR-IA and BMPR-IB. In this model, “the BMP-mediated induction of receptor IB accounts for features of stem cell proliferation, identity, differentiation, and death,” says McKay.

Expression of mutant BMP receptors in CNS stem cells in vitro and in transgenic mice led to...