Protein kinase involved in the activation of the MAP signaling cascade. May play a role in transducing specific signals in neural cells. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binds 2 Zn(2+) ions per subunit. In quiescent cells, maintained in an inactive state via an intramolecular interaction between the protein kinase and N-terminal domains. Following mitogen-mediated cell activation, binds via its RGB domain to active HRAS (GTP-bound) which releases the inhibitory intramolecular interaction between the two domains. This allows the MAP2K1-mediated dimerization of KSR1 or KSR2, and BRAF which activates BRAF. Expressed preferentially in neural tissue. Phosphorylated. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. RAF subfamily.