MAPT and Alzheimer disease: We determined that not only K48- and K63-linked ubiquitin chains, but also M1-linked linear ubiquitin, which regulates NF-κB activation and the cell death pathway, are involved in inclusions from OPTN-associated fALS and sALS patients, and in tau neurofibrillary tangles from Alzheimer’s disease patients [20,22,23].