Related Experiment Video
Updated: Jul 13, 2026

07:08
The Lambda Select cII Mutation Detection System
Published on: April 26, 2018
p51/p63 Inhibits ultraviolet B-induced apoptosis via Akt activation
1Department of Dermatology, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan.
Oncogene
|July 27, 2007
Summary
The p53 family member DeltaNp51B protects skin cells from UV-B-induced apoptosis. Its downregulation enhances cell death, while TAp51B expression significantly reduces it, revealing a novel epidermal protection mechanism.
Area of Science:
- Dermatology
- Molecular Biology
- Cellular Biology
Background:
- The epidermis requires protection against ultraviolet-B (UV-B) induced apoptosis.
- p53 is crucial for this protective response.
- The role of p53 family member DeltaNp51B in UV-B apoptosis is largely unknown.
Purpose of the Study:
- To investigate the role of DeltaNp51B in UV-B-induced keratinocyte apoptosis.
- To determine the protective mechanisms of p51 isoforms against UV-B irradiation.
Main Methods:
- UV-B irradiation of keratinocytes.
- Analysis of p53 and DeltaNp51B expression levels.
- Small interfering RNA (siRNA) mediated knockdown of DeltaNp51B.
- Exogenous expression of DeltaNp51B and TAp51B.
- Assessment of apoptosis and Akt phosphorylation.
Main Results:
- DeltaNp51B levels transiently increased then decreased in UV-B irradiated keratinocytes undergoing apoptosis.
- p53 levels increased with delayed kinetics.
- DeltaNp51B knockdown augmented UV-B-induced apoptosis.
- TAp51B expression significantly decreased UV-B-induced apoptosis.
- p51-mediated apoptosis blockade was dependent on Akt phosphorylation and activation of a survival pathway.
Conclusions:
- DeltaNp51B acts as a suppressor of UV-B-induced keratinocyte apoptosis.
- TAp51B also confers significant protection against UV-B-induced apoptosis.
- The p51 family plays a critical role in protecting the epidermis from UV-B damage by preventing excessive keratinocyte depletion.
Related Concept Videos
The Intrinsic Apoptotic Pathway
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Abnormal Proliferation
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
DNA Damage Can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
DNA Damage can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
Negative Regulator Molecules
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
Mutations
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...