Genome-wide kinase-chromatin interactions reveal the regulatory network of ERK signaling in human embryonic stem cells.

The extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase signal-transduction cascade is one of the key pathways regulating proliferation and differentiation in development and disease. ERK signaling is required for human embryonic stem cells' (hESCs') self-renewing property. Here, we studied the convergence of the ERK signaling cascade at the DNA by mapping genome-wide kinase-chromatin interactions for ERK2 in hESCs. We observed that ERK2 binding occurs near noncoding genes and histone, cell-cycle, metabolism, and pluripotency-associated genes. We find that the transcription factor ELK1 is essential in hESCs and that ERK2 co-occupies promoters bound by ELK1. Strikingly, promoters bound by ELK1 without ERK2 are occupied by Polycomb group proteins that repress genes involved in lineage commitment. In summary, we propose a model wherein extracellular-signaling-stimulated proliferation and intrinsic repression of differentiation are integrated to maintain the identity of hESCs.