TBK1 and frontotemporal dementia: Co-expression of UBQLN2 with TBK1 enhanced the protein level of TBK1 as well as the phosphorylation of both TBK1 and IRF3, and this phosphorylation was reduced by ALS/FTD-linked mutations in UBQLN2, and no altered TBK1 and IRF3 phosphorylation was exhibited in cells that co-expressed with UBQLN1 with TBK1.