(photo: Shutterstock) 

(photo: Shutterstock) 

By Abigail Klein Leichman - April 14, 2015

Originally appeared here in Israel21c 

A particular protein that defies the cell’s normal system of tagging and banishing defective or no longer needed proteins seems to play a significant role in suppressing malignant growth, according to Israeli researchers.

The study was conducted at the Technion-Israel Institute of Technology in the laboratory of Professor Aaron Ciechanover, who won a Nobel Prize in chemistry in 2004 with colleague Avram Hershko and Irwin Rose of the University of California-Irvine.

Led by Dr. Yelena Kravtsova-Ivantsiv, the research team included students and physicians from Rambam, Carmel and Hadassah medical centers. They found the previously unknown p50 protein  during ongoing research on the ubiquitin system, which rids cells of earmarked proteins by sending them for destruction in the cell’s proteasome area.

They discovered that p105, a long precursor of a key cell regulator called NF-κB, sometimes fails to be completely broken down in the proteasome. In those cases, p105 is only shortened and becomes a protein they dubbed p50.

Using samples of human tumors and models of human tumors grown in mice, they then attempted to decipher the decision-making mechanism that determines whether the tagged p105 gets fully degraded or transformed into p50.

The decision between these two options has important implications. Read More