ALS-associated mutations in TDP-43 increase its stability and promote TDP-43 complexes with FUS/TLS

SC Ling, CP Albuquerque, JS Han… - Proceedings of the …, 2010 - National Acad Sciences
SC Ling, CP Albuquerque, JS Han, C Lagier-Tourenne, S Tokunaga, H Zhou, DW Cleveland
Proceedings of the National Academy of Sciences, 2010National Acad Sciences
Dominant mutations in two functionally related DNA/RNA-binding proteins, trans-activating
response region (TAR) DNA-binding protein with a molecular mass of 43 KDa (TDP-43) and
fused in sarcoma/translocation in liposarcoma (FUS/TLS), cause an inherited form of ALS
that is accompanied by nuclear and cytoplasmic aggregates containing TDP-43 or FUS/TLS.
Using isogenic cell lines expressing wild-type or ALS-linked TDP-43 mutants and fibroblasts
from a human patient, pulse-chase radiolabeling of newly synthesized proteins is used to …
Dominant mutations in two functionally related DNA/RNA-binding proteins, trans-activating response region (TAR) DNA-binding protein with a molecular mass of 43 KDa (TDP-43) and fused in sarcoma/translocation in liposarcoma (FUS/TLS), cause an inherited form of ALS that is accompanied by nuclear and cytoplasmic aggregates containing TDP-43 or FUS/TLS. Using isogenic cell lines expressing wild-type or ALS-linked TDP-43 mutants and fibroblasts from a human patient, pulse-chase radiolabeling of newly synthesized proteins is used to determine, surprisingly, that ALS-linked TDP-43 mutant polypeptides are more stable than wild-type TDP-43. Tandem-affinity purification and quantitative mass spectrometry are used to identify TDP-43 complexes not only with heterogeneous nuclear ribonucleoproteins family proteins, as expected, but also with components of Drosha microprocessor complexes, consistent with roles for TDP-43 in both mRNA processing and microRNA biogenesis. A fraction of TDP-43 is shown to be complexed with FUS/TLS, an interaction substantially enhanced by TDP-43 mutants. Taken together, abnormal stability of mutant TDP-43 and its enhanced binding to normal FUS/TLS imply a convergence of pathogenic pathways from mutant TDP-43 and FUS/TLS in ALS.
National Acad Sciences