RSK2 and its binding partners: an emerging signaling node in cancers.

The growth factor-mediated mitogen-activated protein kinase (MAPK) signaling pathways in cancer development have become increasingly important in the discovery of therapeutic agents for the treatment of cancer. RSK2 has been historically overlooked in studies regarding its involvement in physiology and signaling pathways related to human diseases, except for Coffin-Lowry syndrome, because it is located downstream of ERKs. For the last 25 years, the authors' laboratory has made groundbreaking discoveries regarding the role of RSK2, especially by elucidating its binding partners, signaling network, and crosstalk. RSK2 is an important emerging target for developing anticancer drugs. Nevertheless, further studies on the detailed mechanism and signaling network are necessary to avoid the unexpected effects of RSK2 inhibitors. This paper describes a new paradigm of RSK2, where it works as a signaling node to modulate diverse cellular processes, including cell proliferation and transformation, cell cycle regulation, chromatin remodeling, and immune response and inflammation regulation.