BACKGROUND: Regulation of mRNAs is one way to control protein levels and thereby 
important cellular processes such as growth, invasion and apoptosis. G3BPs 
constitute a family of mRNA-binding proteins, shown to be overexpressed in 
several cancer types, including breast, colon and pancreas cancer. G3BP has been 
reported to both stabilize and induce degradation of specific mRNAs.
RESULTS: Here, we show that G3BP1, but not G3BP2, supports proliferation of 
several breast cancer cell lines. Global gene expression analyses of G3BP1- and 
G3BP2-depleted cells indicate that primarily G3BP1, and much less G3BP2, 
influences mRNA expression levels. Peripheral myelin protein 22 (PMP22) was one 
gene that was significantly influenced by G3BP1 depletion which led to a 2-3 
fold increased expression. Depletion of PMP22 resulted in increased 
proliferation and the G3BP1-mediated effect on proliferation was not seen upon 
PMP22-depletion.
CONCLUSIONS: This indicates a novel role for G3BP1 in the regulation of cell 
proliferation in breast cancer cells, perhaps via a regulatory effect on PMP22 
expression.