Importantly, M1-ubiquitin reportedly facilitates fibrillar aggregates formation than that of K48- and K63-linked ubiquitin chains (Morimoto et al., 2015), suggesting that M1-ubiquitination is crucial for the development of neurodegenerative diseases through the promotion of LLPS, oligomerization, and aggregate formation. The gene discussed is RPS27A; the disease is neurodegenerative disease.