Hongbo Hu's Lab
The State Key Laboratory of Biotherapy Si-Chuan University
KPC1 controls p105 processing and tumor growth

p105 (NF-kB1) is a processor of p50. Only part of p105 isprocessed to p50 by a proteasome dependent manner. However, how this process isregulated is unknown. Recent study published in Cell indicates an ubiquitine E3ligase, KPC1, also called RNF123, is a key regulator of p105 processing. KPC1binds to the ankyrin repeats domain of p105 and ubiquitinase it and leading tothe processing of p105, in both basal level and following the stimulation. KPC1inhibits tumor growth by generating p50-p50 dimer (tumor-suppressive), whichmight reduce the p50-p65 dimer (tumorigenic). This study reveals a basalmechanism of p105 processing, also indicates the important function of p65-p50and p50-p50 in tumor growth.

The original paper is http://dx.doi.org/10.1016/j.cell.2015.03.001