PCNA-p21 complex
Definition
Target type: cellularcomponent
A protein complex that contains the cyclin-dependent protein kinase inhibitor p21WAF1/CIP1 bound to PCNA; formation of the complex inhibits DNA replication. [GOC:mah, PMID:7911228, PMID:7915843]
The PCNA-p21 complex is a heteromeric protein complex involved in cell cycle regulation. PCNA (proliferating cell nuclear antigen) is a ring-shaped protein that acts as a sliding clamp, encircling DNA and serving as a processivity factor for DNA polymerases during DNA replication. p21, also known as CDKN1A (cyclin-dependent kinase inhibitor 1A), is a cyclin-dependent kinase (CDK) inhibitor protein. The formation of the PCNA-p21 complex plays a critical role in regulating the transition from the G1 to S phase of the cell cycle. When p21 binds to PCNA, it blocks the access of DNA polymerases to the DNA strand, inhibiting DNA replication and preventing the cell from entering the S phase. This inhibitory function of p21 is essential for maintaining genomic stability and preventing uncontrolled cell proliferation. The cellular component of the PCNA-p21 complex is primarily located in the nucleus of eukaryotic cells, where DNA replication and repair processes occur. Within the nucleus, the complex associates with the chromatin, which is the complex of DNA and proteins that makes up chromosomes. The specific localization of the complex within the nucleus may vary depending on the cell cycle stage and the specific cellular process being regulated. The PCNA-p21 complex can also be found in other cellular compartments, such as the cytoplasm, but its primary function is associated with its nuclear localization.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Proliferating cell nuclear antigen | A proliferating cell nuclear antigen that is encoded in the genome of human. [PRO:DNx] | Homo sapiens (human) |
Compounds (7)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 3,3',5-triiodothyroacetic acid | tiratricol : A monocarboxylic acid that is (4-hydroxy-3,5-diiodophenyl)acetic acid in which the phenolic hydroxy group has been replaced by a 4-hydroxy-3-iodophenoxy group. It is a thyroid hormone analogue that has been used in the treatment of thyroid hormone resistance syndrome. | ||
| 3,3',5-triiodothyropropionic acid | aromatic ether | ||
| thyroxine | thyroxine : An iodothyronine compound having iodo substituents at the 3-, 3'-, 5- and 5'-positions. Thyroxine: The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism. | 2-halophenol; iodophenol; L-phenylalanine derivative; non-proteinogenic L-alpha-amino acid; thyroxine; thyroxine zwitterion | antithyroid drug; human metabolite; mouse metabolite; thyroid hormone |
| triiodothyronine | 3,3',5-triiodo-L-thyronine : An iodothyronine compound having iodo substituents at the 3-, 3'- and 5-positions. Although some is produced in the thyroid, most of the 3,3',5-triiodo-L-thyronine in the body is generated by mono-deiodination of L-thyroxine in the peripheral tissues. Its metabolic activity is about 3 to 5 times that of L-thyroxine. The sodium salt is used in the treatment of hypothyroidism. Triiodothyronine: A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3. | 2-halophenol; amino acid zwitterion; iodophenol; iodothyronine | human metabolite; mouse metabolite; thyroid hormone |
| 3,5-diiodothyronine, (l)-isomer | phenylalanine derivative | ||
| 3,3'-diiodothyronine | 3,3'-diiodothyronine: RN given refers to unlabeled cpd without isomeric designation | 3,3'-diiodothyronine; amino acid zwitterion | human metabolite |
| 3,5-diiodothyropropionic acid | 3,5-diiodothyropropionic acid : A monocarboxylic acid that is (4-hydroxy-3,5-diiodophenyl)propanoic acid in which the phenolic hydroxy group has been replaced by a 4-hydroxyphenyl group. An ionotropic analogue of L-thyroxine. 3,5-diiodothyropropionic acid: a cardiotonic thyroid hormone analog | aromatic ether; monocarboxylic acid; organoiodine compound; phenols |