CHN1, also known as chimerin 1, is a TPase-activating protein for ras-related p21-rac and a phorbol ester receptor. It is predominantly expressed in neurons, and plays an important role in neuronal signal-transduction mechanisms. CHN1 is involved in the assembly of neuronal locomotor circuits as a direct effector of EPHA4 in axon guidance. The CHN1 gene provides instructions for making two very similar proteins called α1-chimaerin and α2-chimaerin. These proteins play an important role in the early development of the nervous system. In particular, they help regulate complex chemical signaling pathways during the formation and development of nerve cells (neurons). These proteins help guide the growth of axons and dendrites, which are specialized extensions of neurons that transmit and receive nerve impulses throughout the nervous system.