Scientists at the U.S. Scripps Research Institute (TSRI) have discovered a protein that fine-tunes the cellular clock involved in aging, EurekAlert reported.

This novel protein, named TZAP, binds the ends of chromosomes and determines how long telomeres, the segments of DNA that protect chromosome ends, can be. Understanding telomere length is crucial because telomeres set the lifespan of cells in the body, dictating critical processes such as aging and the incidence of cancer.

"This protein sets the upper limit of telomere length," explained Lazzerini Denchi. "This allows cells to proliferate--but not too much."

For the last few decades, the only proteins known to specifically bind telomeres is the telomerase enzyme and a protein complex known as the Shelterin complex. The discovery TZAP, which binds specifically to telomeres, was a surprise since many scientists in the field believed there were no additional proteins binding to telomeres.