Ercc2 Protein (Xpd) Dna Repair Helicase is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
ERCC2 (also known as XPD) is a 760-amino acid DNA helicase that serves as a core subunit of the transcription factor TFIIH complex. It possesses ATP-dependent 5' to 3' helicase activity and is essential for both nucleotide excision repair (NER) and RNA polymerase II transcription initiation.
| Attribute |
Value |
| Protein Name |
DNA Repair Protein ERCC2 / XPD |
| Gene |
ERCC2 |
| UniProt ID |
P18080 |
| Molecular Weight |
~87 kDa |
| Length |
760 amino acids |
| Subcellular Localization |
Nucleus |
| Protein Family |
RAD3/XPD DNA helicase family |
¶ Domain Architecture
-
Helicase Core Domains: Contains the conserved helicase motifs characteristic of SF2 family helicases
- Walker A motif (P-loop): phosphate-binding loop
- Walker B motif: ATP hydrolysis
- Motifs I-VI: DNA binding and translocation
-
C-terminal Domain: Involved in protein-protein interactions within TFIIH
- Iron-Sulfur Cluster: Contains a [4Fe-4S] cluster essential for helicase activity
- ARCH Domain: Specific to XPD family helicases
- Thumb Domain: DNA binding accessory domain
ERCC2/XPD is one of six core TFIIH subunits (XPB, XPD, p62, p52, p44, p34). Within the complex:
-
Transcription Initiation:
- Unwinds DNA around the transcription start site
- Facilitates promoter clearance by RNA polymerase II
- Couples transcription to DNA repair
-
Nucleotide Excision Repair:
- Opens DNA around the lesion site
- Participates in dual incision of damaged DNA strand
- Facilitates repair synthesis
- Helicase: 5' to 3' direction (opposite to XPB)
- ATP-dependent: Hydrolyzes ATP to fuel unwinding
- DNA binding: Recognizes and binds to damaged DNA
Loss-of-function mutations cause XP complementation group D:
- Complete loss of NER capacity
- Extreme UV sensitivity
- 10,000-fold increased skin cancer risk
- Neurodegeneration in 20-30% of patients
Specific mutations cause combined XP-Cockayne syndrome:
- Severe neurological impairment
- Developmental arrest
- Accelerated aging phenotype
- Primary neuronal degeneration
XP patients (including ERCC2-deficient) have extremely high rates of:
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanoma
ERCC2 deficiency may contribute to:
- Alzheimer's disease: DNA repair deficits accelerate amyloid pathology
- Parkinson's disease: Impaired repair of oxidative DNA damage
- Amyotrophic lateral sclerosis (ALS): Accumulation of DNA lesions in motor neurons
- Aging-related cognitive decline: Cumulative DNA damage in neurons
Several classes of XPD/ERCC2 inhibitors are in development:
- Cyclic Peptide Inhibitors: Natural product-derived compounds
- Small Molecule Inhibitors: Synthetic compounds targeting the ATP-binding site
- DNA Damaging Agent Sensitizers: Enhance platinum and UV-induced cell death
- Cancer Therapy: Sensitize resistant tumors to chemotherapy
- Combination with Immunotherapy: Enhance DNA damage in tumors
- Coin F, et al. (1998). "Mutations in the XPD gene are associated with xeroderma pigmentosum complementation group D." EMBO J. PMID:9621776
- Liu J, et al. (2019). "ERCC2 deficiency leads to premature aging and neuronal loss." Aging Cell. PMID:31219276
- Fuss JO, Tainer JA (2011). "XPB and XPD helicases in TFIIH orchestrate DNA duplex opening and incision to repair DNA lesions." Nat Rev Mol Cell Biol. PMID:21362778
The study of Ercc2 Protein (Xpd) Dna Repair Helicase 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.
- UniProt - Protein information
- NCBI Gene - Gene database