HBEGF: an EGF-like growth factor with FGF23-like activity?

Renal signaling networks downstream of FGF23 are not well delineated, but elucidating them may offer an opportunity to control target genes independent of FGF23 in states of dysregulated mineral metabolism. Ni et al. identify HBEGF as a paracrine/autocrine factor in the proximal tubules of mice that mimics the inductive effect of FGF23 on the vitamin D–catabolizing enzyme 24-hydroxylase through a common mitogen-activated protein kinase–dependent pathway. An understanding of how these findings relate to human disease is eagerly anticipated.