MARK1 and early-onset autosomal dominant Alzheimer disease: MARK/Par-1 can phosphorylate Tau at serine 262[31], which has been shown to be hyperphosphorylated in postmortem Alzheimer’s disease (AD) patient brains[52] and it has been demonstrated that MARK/Par-1 can function as a “initiator kinase”[9] for the cascade that hyperphosphorylates Tau.