Key Highlights:
- UV light causes damage to the mRNA in skin cells, which then triggers a wave of cellular responses.
- Such damage activates ribosomes and induces the ribotoxic stress response (RSR).
- Ribotoxic Stress Response (RSR)
- The RSR is recognized as a surveillance mechanism responding to the presence of RNA damage with inflammatory signaling, recruitment of immune cells, and inflammation of the skin.
- Confirms the crucial role of ZAK gene in RNA damage responses.
What is Sunburn?
Sunburned skin looks red, painful, and damaged due to too much exposure in the sun. The ultraviolet (UV) rays from the sun or a tanning bed burn your skin when you get a sunburn. You don’t have to spend a whole day at the beach or swimming pool to get a sunburn. Multiple sunburns can cause premature skin aging and skin cancer.
Ribosomes
Ribosomes are molecular machines that synthesize proteins in all cells. They are made of RNA and protein, and are found in the cytoplasm of cells.
- How ribosomes work
- Ribosomes read the messenger RNA (mRNA) sequence.
- They translate the genetic code into a string of amino acids.
- The amino acids are added to a growing protein chain.
- When the ribosome reaches a stop codon, it releases the finished protein.
- Types of ribosomes
- 70S ribosomes: Prokaryotic cells that include bacteria and archaea.
- 80S ribosomes: Eukaryotic cells that include plants, animals, and fungi.
- Number of ribosomes in a cell
- The number of ribosomes in a cell depends on the level of its activity in protein synthesis.
- Growing cells contain numerous ribosomes.
- One eukaryotic cell may have as many as 10 million ribosomes.
- Discovery of ribosomes
- George E. Palade discovered the first ribosomes in 1955.
- He won the Nobel Prize in 1974.
The Ribotoxic Stress Response (RSR)
The ribotoxic stress response pathway is a mechanism that senses for stress in cells and initiates stress response programmes. RSR is involved with cell death and inflammation, though it also plays some role in regulation of metabolism.
- How it work?
- The pathway is activated following ribosomal stalling or collision, and the protein MAP3K ZAKα senses the stressed state and can activate the stress-associated mitogen-activated protein (MAP)-kinases p38 and JNK.
- The activated p38 and JNK kinases mediate cell death through pyroptosis and apoptosis, respectively.
- What it Does?
- The RSR is involved in the acute effects of sunburn responses.
- The RSR modulates metabolic responses in cells, nematodes, and mice.
- The RSR modulates blood sugar control, stress hormone production, and survival under starvation conditions.
- What causes it?
- The RSR can be induced by exogenous or endogenous stress signals, plant and microbial toxins, or cell-intrinsic factors.
