MAPT and Alzheimer disease: Furthermore, the possibility exists that some MAO-A inhibitors like harmine that—unlike clorgyline—is a compound with affinity for both MAO-A and DYRK1A (a kinase that phosphorylates tau at multiple AD-related sites and appears in neurofibrillary tangles), may directly compete with tau ligands by binding to DYRK1A in tau tangles rather than through off-target binding to MAO-A [50, 57].