One of the earliest sites on tau to become phosphorylated in the AD brain is Ser262[9], which is located in the KXGS motif in one of the microtubule repeat domains, and that can be phosphorylated by MARK1-4 [10–13], a family of four highly conserved kinases [10, 12, 14]. The gene discussed is MARK1; the disease is Alzheimer disease.