Amyotrophic lateral sclerosis-associated proteins TDP-43 and FUS/TLS function in a common biochemical complex to co-regulate HDAC6 mRNA.
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease that preferentially targets motor neurons. It was recently found that dominant mutations in two related RNA-binding proteins, TDP-43 (43-kDa TAR DNA-binding domain protein) and FUS/TLS (fused in sarcoma/translated in liposarcoma) cause a subset of ALS. The convergent ALS phenotypes associated with TDP-43 and FUS/TLS mutations are suggestive of a functional relationship; however, whether or not TDP-43 and FUS/TLS operate in common biochemical pathways is not known. Here we show that TDP-43 and FUS/TLS directly interact to form a complex at endogenous expression levels in mammalian cells. Binding was mediated by an unstructured TDP-43 C-terminal domain and occurred within the context of a 300-400-kDa complex that also contained C-terminal cleavage products of TDP-43 linked to neuropathology. TDP-43 C-terminal fragments were excluded from large molecular mass TDP-43 ribonucleoprotein complexes but retained FUS/TLS binding activity. The functional significance of TDP-43-FUS/TLS complexes was established by showing that RNAi silencing of either TDP-43 or FUS/TLS reduced the expression of histone deacetylase (HDAC) 6 mRNA. TDP-43 and FUS/TLS associated with HDAC6 mRNA in intact cells and in vitro, and competition experiments suggested that the proteins occupy overlapping binding sites. The combined findings demonstrate that TDP-43 and FUS/TLS form a functional complex in intact cells and suggest that convergent ALS phenotypes associated with TDP-43 and FUS/TLS mutations may reflect their participation in common biochemical processes.
Kim
Sang Hwa
SH
Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA.
Shanware
Naval P
NP
Bowler
Michael J
MJ
Tibbetts
Randal S
RS
D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases / Q000737:chemistry*; D006801:Humans; D009046:Motor Neurons / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D025941:Protein Interaction Mapping; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034702:RNA-Binding Protein FUS / Q000737:chemistry*; D016601:RNA-Binding Proteins / Q000737:chemistry
D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D034702:RNA-Binding Protein FUS; D016601:RNA-Binding Proteins; C433811:HDAC6 protein, human; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases