checkpoint clamp complex

Definition

Target type: cellularcomponent

Conserved heterotrimeric complex of PCNA-like proteins that is loaded onto DNA at sites of DNA damage. [PMID:12531008]

The checkpoint clamp complex is a crucial component of DNA replication and repair pathways. It acts as a sliding clamp that encircles DNA and facilitates the recruitment and retention of various DNA processing enzymes to the site of DNA damage or replication fork. The complex is composed of several protein subunits, with the core unit being a dimer of the proliferating cell nuclear antigen (PCNA) protein. PCNA is a ring-shaped protein that encircles DNA, providing a platform for the assembly of other proteins involved in DNA processing.

The checkpoint clamp complex plays a central role in the DNA damage response (DDR). When DNA damage occurs, the complex is loaded onto the DNA at the site of the lesion. This loading event triggers a cascade of signaling events that lead to cell cycle arrest, DNA repair, or apoptosis. The checkpoint clamp complex also plays a role in regulating DNA replication by ensuring that the process is accurate and efficient.

Here are some of the key features of the checkpoint clamp complex:

* **Structure:** The core of the checkpoint clamp complex is the PCNA dimer, which forms a ring around the DNA. This ring structure provides a stable platform for the assembly of other proteins.
* **Dynamic Assembly and Disassembly:** The complex is assembled and disassembled in a tightly regulated manner. Loading of the complex onto DNA is mediated by specialized loading factors, while removal of the complex is carried out by dedicated unloading factors.
* **Recruitment of DNA Processing Enzymes:** The checkpoint clamp complex acts as a scaffold for the recruitment and retention of DNA processing enzymes, such as DNA polymerases, DNA ligases, and DNA repair enzymes.
* **Regulation of DNA Replication and Repair:** The checkpoint clamp complex plays a critical role in the regulation of DNA replication and repair by ensuring the accuracy and efficiency of these processes.
* **Role in Cell Cycle Control:** The complex is involved in the regulation of cell cycle progression by triggering cell cycle arrest in response to DNA damage.

The checkpoint clamp complex is a complex and highly regulated structure that plays a crucial role in maintaining genome integrity. Its dysfunction can lead to various cellular abnormalities, including cancer.'
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Proteins (1)

Compounds (1)