TDP-43 Protein is a protein. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
TAR DNA-binding protein 43 (TDP-43) is a highly conserved RNA/DNA-binding protein that plays crucial roles in RNA metabolism, including transcription, splicing, and transport. Pathological aggregation of TDP-43 is a hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD).
¶ Gene and Structure
The TARDBP gene on chromosome 1p36.22 encodes the TDP-43 protein, which consists of:
- N-terminal domain (1-102 aa): Contains nuclear localization signal (NLS)
- RNA recognition motif (RRM1, 106-176 aa): Binds RNA/DNA
- RNA recognition motif (RRM2, 191-259 aa): Second RNA-binding domain
- C-terminal domain (260-414 aa): Prion-like domain enriched in glutamine (Q) and asparagine (N) residues
TDP-43 is predominantly nuclear but can shuttle between nucleus and cytoplasm. Its normal functions include:
- Transcriptional regulation: Binds to TAR DNA elements and regulates gene transcription
- RNA splicing: Involved in alternative splicing of pre-mRNA
- RNA stability: Regulates mRNA stability and transport
- Stress granule formation: Part of stress response mechanisms
- MicroRNA processing: Participates in miRNA biogenesis
Pathological TDP-43 aggregation is found in:
- Amyotrophic Lateral Sclerosis (ALS): ~95% of ALS cases show TDP-43 inclusions
- Frontotemporal Dementia (FTD): Particularly the GRN (progranulin) mutation cases
- ALS-FTD spectrum: Overlapping clinical presentations
TDP-43 pathology involves several mechanisms:
- Cytoplasmic aggregation: Mislocalization from nucleus to cytoplasm
- Loss of nuclear function: Reduced TDP-43 in nucleus impairs RNA processing
- Gain of toxic function: Cytoplasmic aggregates may be directly toxic
- Stress granule dysregulation: Abnormal stress granule dynamics
- RNA metabolism disruption: Aberrant processing of target mRNAs
Mutations in TARDBP are causally linked to ALS:
- Over 50 pathogenic mutations identified
- Most are missense mutations in the C-terminal prion-like domain
- Mutations promote aggregation and mislocalization
Related genes:
- GRN (progranulin): Mutations cause FTD with TDP-43 pathology
- C9orf72: Hexanucleotide repeat expansions cause ALS/FTD with TDP-43
- TBK1: Mutations linked to ALS/FTD, affects autophagy
Current research directions include:
- Antisense oligonucleotides: Targeting TARDBP mRNA for degradation
- Small molecule inhibitors: Compounds that prevent aggregation
- Gene therapy: Viral vector delivery of corrected genes
- Autophagy enhancers: Promoting clearance of aggregates