Furthermore, GPRC5B facilitates Fyn-dependent phosphorylation of sphingomyelin synthase 2 (SMS2), which activates the diacylglycerol/protein kinase C/c-Jun N-terminal kinase (DAG/PKC/JNK) signaling cascade, a key pathway in the pathogenesis of insulin resistance [109]. The gene discussed is SGMS2; the disease is Insulin resistance.