DNA repair protein strongly associated with breast cancer

The protein, Brca1 is a DNA repair protein whose absence or misfunction is associated with breast cancer.

Over one’s lifetime, damage to DNA through the environment is inevitable, and a class of proteins have been found that try to repair DNA when damage is detected. Brca1 is responsible for repairing double stranded breaks in DNA. Brca1 works as a team with a few other proteins to locate, sense and signal for the repair of damaged DNA.

In the absence of a functional Brca1 protein, cells develop chromosomal instability more quickly and greatly increase the probability of damaged cells becoming cancerous.

Brca1 is a fairly large protein with a number of functional domains.1

  • A Ring Domain responsible for marking other proteins for degradation with Ubiquitin .
  • Rad50 , Rad51 and PalB2 binding domains - responsible for bringing other DNA repair proteins to sites of damage.
  • Nuclear localization signals that make sure Brca1 gets to the nucleus, where the DNA is.
  • The C-terminal BRCT domain seems responsible for integrating signals that sense DNA damage.

Sequencing a person’s genome can reveal whether or not the DNA that encodes for Brca1 contains mutations that would result in a truncated or mis-formed version. If the DNA that encodes for Brca1 is mutated, especially in ways that prevent some of the above functions, then cells that contain that DNA are more likely to be unable to repair routine DNA damage. Testing for particular DNA sequences that indicate that Brca1 is damaged was the subject of a recent decision by the Supreme Court of the United States.