Xpc-rad23b complex

Definition

The xpc-rad23b complex is a protein assembly that plays a crucial role in the nucleotide excision repair (NER) pathway, which is responsible for repairing bulky DNA lesions and damaged nucleotides caused by environmental factors like UV light. This complex is essential for recognizing DNA damage and initiating the repair process, showcasing the importance of protein interactions in maintaining genomic integrity.

5 Must Know Facts For Your Next Test

1. The xpc-rad23b complex is composed of the XPC protein and RAD23B, both of which are essential for recognizing DNA damage during the NER process.
2. The complex specifically binds to damaged DNA sites and recruits other proteins necessary for effective repair, thereby acting as an early sensor in the NER pathway.
3. Mutations in the XPC gene can lead to impaired DNA damage recognition, contributing to disorders like Xeroderma Pigmentosum.
4. The xpc-rad23b complex is known to interact with additional proteins such as TFIIH, which is involved in unwinding DNA around the site of damage to facilitate repair.
5. Research has shown that proper functioning of the xpc-rad23b complex is critical for cellular responses to environmental stressors, including UV exposure.

Review Questions

• How does the xpc-rad23b complex contribute to the nucleotide excision repair process?
  • The xpc-rad23b complex plays a pivotal role in nucleotide excision repair by first recognizing and binding to damaged DNA sites. This recognition is crucial for triggering the recruitment of other repair proteins, including those necessary for unwinding the DNA. The complex's ability to initiate these interactions helps ensure that bulky lesions are effectively repaired, maintaining genomic stability.
• Discuss the implications of mutations in the XPC gene on human health and disease.
  • Mutations in the XPC gene can severely disrupt the function of the xpc-rad23b complex, leading to impaired recognition of DNA damage. This deficiency significantly increases an individual's susceptibility to skin cancers, particularly in cases of Xeroderma Pigmentosum, where affected individuals experience extreme sensitivity to UV radiation. The lack of effective repair mechanisms not only raises cancer risk but also emphasizes the importance of this complex in protecting against environmental stressors.
• Evaluate the role of the xpc-rad23b complex within the broader context of cellular responses to DNA damage and environmental stress.
  • The xpc-rad23b complex serves as a critical first responder in detecting DNA damage from environmental stressors like UV radiation. Its functionality within the nucleotide excision repair pathway exemplifies how protein complexes coordinate cellular responses to maintain genomic integrity. The complexity of this response illustrates how failures in such systems can lead to significant health risks, including cancer development and genetic disorders. Understanding this mechanism provides insight into potential therapeutic targets for enhancing DNA repair processes.

Related terms

Nucleotide Excision Repair (NER): A DNA repair mechanism that removes a wide range of DNA damage, including bulky adducts, by excising a short single-strand segment containing the lesion.

DNA Damage Response (DDR): A complex signaling network that detects DNA damage and orchestrates cellular responses to repair the damage, prevent mutations, and maintain genomic stability.

Xeroderma Pigmentosum: A genetic disorder characterized by an extreme sensitivity to UV radiation due to defects in the NER pathway, leading to a high risk of skin cancer.