[TDP-43](/proteins/tdp-43) (TAR DNA-binding protein-43, encoded by the TARDBP gene) is a heterogeneous nuclear ribonucleoprotein (hnRNP) that plays critical roles in RNA processing, including splicing, stability, transport, and translation. Pathological aggregation of [TDP-43](/mechanisms/tdp-43-proteinopathy) in [neurons](/entities/neurons) and glia is the hallmark of amyotrophic lateral sclerosis (ALS) and the majority of frontotemporal dementia (FTD) cases, making TDP-43 one of the most important proteins in neurodegenerative disease research.
Introduction
TDP-43 is a 414-amino acid protein that belongs to the hnRNP family. Originally characterized as a transcriptional repressor binding to the TAR element of HIV-1, TDP-43 has emerged as a fundamental RNA-binding protein with roles in nearly every aspect of RNA metabolism. The discovery of TARDBP mutations as a cause of familial ALS in 2008 established TDP-43 as a central player in neurodegeneration. This page provides comprehensive information about TDP-43's structure, functions, disease mechanisms, and therapeutic strategies. [@kwiatkowski2009]
[@gassetrosa2019]
Molecular Structure
Domain Architecture
TDP-43 contains several distinct functional domains:
N-terminal domain (residues 1-102): Contains a nuclear localization signal (NLS) and mediates protein-protein interactions. This domain is relatively conserved and participates in homodimerization.
RNA recognition motif 1 (RRM1, residues 106-176): The primary RNA-binding domain with the canonical RNP1 and RNP2 sequences. Binds UG-rich RNA sequences with high affinity.
RNA recognition motif 2 (RRM2, residues 191-259): A second RRM that contributes to RNA binding specificity and affinity. The two RRMs work cooperatively.
Glycine-rich low-complexity domain (residues 274-414): This C-terminal region is prion-like and prone to aggregation. Contains the QGSY region (Gln-Gly-Ser-Tyr) characteristic of many RNA-binding proteins. Most ALS/FTD mutations cluster here.
Nuclear export signal (NES): A leucine-rich sequence enabling cytoplasmic localization under certain conditions.
Post-Translational Modifications
TDP-43 undergoes numerous modifications:
Phosphorylation: At S379, S403, S404, and S409/S410 (the most studied sites) in pathological inclusions
Ubiquitination: Pathological aggregates are ubiquitinated
SUMOylation: Affects subcellular localization
Acetylation: At K263, K331, affects RNA binding
Methylation: Arginine methylation affects localization and function
Normal Physiological Functions
RNA Processing
Alternative Splicing
TDP-43 regulates alternative splicing of numerous transcripts:
CFTR exon 9: Classic example of TDP-43-mediated skipping
neuronal transcripts: Including [tau](/proteins/tau) (MAPT), GABA receptors, and others
GRN: Progranulin and TDP-43 have intersecting pathways
FTD-TDP types: Share pathological mechanisms
Background
The study of Tardbp Tdp 43 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.