Saturday, November 8, 2014

Rap1 Proteins Role at Telomeres Solved

Mice and humans share numerous commonalities including their telomeres, the protective ends on chromosomes.  However, there is one particular protein, Rap1, at telomeres whose role has perplexed scientists for years. The Rap1 protein binds telomeres and then helps guard and maintain the telomere allowing the telomere to maintain its protective function. Previous research showed that in humans Rap1 played a crucial role while in mice the protein appeared to play only a minor role. This discrepancy was difficult to explain since both mice and humans are mammals.



New research at RockefellerUniversity has solved the discrepancy in the Rap1 protein. Researchers have discovered that the protein contributes very little if any to the protection of the telomere. However, while the research has solved the role of Rap1 in the protection of telomeres, another question was raised due to the research. This question is if Rap1 doesn’t protect telomeres why has evolution maintained the protein in both mice and humans?


Previous research has shown that dysfunctional telomeres have been linked to aging and cancer. Additionally, in prior research there were no changes in mice telomere length observed; however, mice have much longer telomeres so slight changes are more difficult to detect than they are in humans. Rap1 is one of six shelterin components in humans and mice, and dates back all the way back to yeast and a single-celled parasite called trypanosomes.

Shaheen Kabir, a graduate student in the lab, stated, “"We piled up a lot of negative data looking for effects of removing Rap1 from human telomeres. We observed no fusions, no significant changes in telomere length, no turning on of DNA damage signaling, the list goes on.”

The researchers concluded the possibility that Rap1 has a redundant function that overlaps with other shelterin components cannot be dismissed; however, it is most likely the protein must fill some other, unrelated role. Rap1 was first identified as a protein that turns genes on or off and research in mammalian cells have shown that the protein has a strong influence on genes related to body weight and metabolism which explains why evolution has maintained the protein.


This article was interesting because it discussed research that bought clarity to a previously unclear discrepancy. While the research does not provide anything groundbreaking it brings closer to an issue that has baffled scientists for decades and discoveries such as this are always important. 





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