About SIRT/ Sirtuin:
Sirtuin proteins (or SIRT) are a class of proteins that have been shown to regulate the aging process, mitochondrial function, gene expression, and cellular metabolism. They carry out these functions by deacetylating specific lysine residues in other proteins.
Sirtuin proteins work by removing acetyl groups from specific lysine residues in other proteins. In the nucleus, they are found mainly as a homodimer (a protein that consists of two identical polypeptide chains) and bind to specific DNA sequences adjacent to telomeres. They contact histones on the DNA and, in turn, deacetylate the lysine residues on these histones. It results in a change of DNA transcription, regulating the epigenetic state of telomeres.
When SIRT are bound to an acetylated histone, they can recruit other proteins which contain a lysine residue. The process of recruitment is facilitated by the structures that form between the protein and DNA. In addition to that, once recruited, these enzymes deacetylated for SIRT's role to continue.
A lot of current research is being done on the SIRT proteins and their role in aging. Deacetylating a particular residue, known as lysine 130 (K130), decreased acetylated HSP90 protein levels. It means an increase in autophagy activity which helps fight off inflammatory responses and prevent age-related diseases.
The findings are very promising as they help understand how to slow down the aging process. However, more research is needed before making any concrete conclusions on whether SIRT proteins play a role in longevity or not.