Fig. 7. Scheme of the signalling pathway from HA through GPR37 to stimulate mitosis. After binding of HA to GPR37 with or without help of the coreceptor SorLA, a pertussis-toxin-sensitive inhibitory G protein (Gi) is activated, which interacts through the phosphoinositide 3-kinase (PI3K) and the calcium-calmodulin dependent kinase II (CaMK) with a Ca²⁺ channel of the transient receptor potential family (TRPV2-like). The resulting Ca²⁺ influx activates a Ca²⁺-dependent K⁺ channel of the small and intermediate conductance family (SK4-like), leading to hyperpolarisation, which is a prerequisite for cells to enter mitosis. Dashed lines indicate hypothetical pathways.