Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2009-6-22
pubmed:abstractText
The inhibitor of cyclin-dependent kinases p21CDKN1A plays a fundamental role in several pathways involved in the DNA damage response, like checkpoint-mediated cell cycle arrest, transcription, apoptosis, and DNA repair. Although p21 protein level is regulated by proteasomal degradation, the relationship of this process with DNA repair pathways is not yet clear. In addition, the role of protein/protein interaction in regulating turnover of p21 protein, is controversial. Here, we show that in human fibroblasts treated with agents inducing lesions repaired through nucleotide excision repair (NER), or base excision repair (BER), p21 degradation was triggered more by the extent, than by the type of DNA damage, or consequent DNA repair pathway. In fact, lowering the amount of DNA damage resulted in an increased stability of p21 protein. Overexpression of p21 was found to obscure degradation, both for p21wt and a p21 mutant unable to bind PCNA (p21PCNA-). However, when expressed to lower levels, turnover of p21 protein after DNA damage was greatly influenced by interaction with PCNA, since p21PCNA- was more efficiently degraded than wild-type protein. Interestingly, a p21 mutant protein unable to localize in the nucleus because of mutations in the NLS region, was not degraded after DNA damage, thus indicating that nuclear localization is necessary for p21 turnover. Removal of p21 was not required for NER activity, since inhibition of p21 degradation by caffeine did not affect the UV-induced recruitment of repair proteins, such as PCNA and DNA polymerase delta, nor significantly influence DNA repair synthesis, as determined by autoradiography. These results indicate that degradation of p21 is not dependent on a particular DNA repair pathway, and is not required for efficient DNA repair.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1568-7864
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
778-85
pubmed:meshHeading
pubmed-meshheading:19321391-Blotting, Western, pubmed-meshheading:19321391-Cell Line, pubmed-meshheading:19321391-Cell Survival, pubmed-meshheading:19321391-Cells, Cultured, pubmed-meshheading:19321391-Cisplatin, pubmed-meshheading:19321391-Cross-Linking Reagents, pubmed-meshheading:19321391-Cyclin-Dependent Kinase Inhibitor p21, pubmed-meshheading:19321391-DNA Damage, pubmed-meshheading:19321391-DNA Repair, pubmed-meshheading:19321391-Fibroblasts, pubmed-meshheading:19321391-Fluorescent Antibody Technique, pubmed-meshheading:19321391-HeLa Cells, pubmed-meshheading:19321391-Humans, pubmed-meshheading:19321391-Mutation, pubmed-meshheading:19321391-Proliferating Cell Nuclear Antigen, pubmed-meshheading:19321391-Protein Binding, pubmed-meshheading:19321391-Signal Transduction, pubmed-meshheading:19321391-Time Factors, pubmed-meshheading:19321391-Transfection, pubmed-meshheading:19321391-Ultraviolet Rays
pubmed:year
2009
pubmed:articleTitle
Degradation of p21CDKN1A after DNA damage is independent of type of lesion, and is not required for DNA repair.
pubmed:affiliation
Dipartimento di Medicina Sperimentale, sez. Patologia Generale C. Golgi, Università di Pavia, Pavia, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't