Ras-related and Estrogen-Regulated Growth inhibitor (RERG) and Ras-like 11 (RasL11)-like families
RERG (Ras-related and Estrogen- Regulated Growth inhibitor) and Ras-like 11 are members of a novel subfamily of Ras that were identified based on their behavior in breast and prostate tumors, respectively. RERG expression was decreased or lost in a significant fraction of primary human breast tumors that lack estrogen receptor and are correlated with poor clinical prognosis. Elevated RERG expression correlated with favorable patient outcome in a breast tumor subtype that is positive for estrogen receptor expression. In contrast to most Ras proteins, RERG overexpression inhibited the growth of breast tumor cells in vitro and in vivo. RasL11 was found to be ubiquitously expressed in human tissue, but down-regulated in prostate tumors. Both RERG and RasL11 lack the C-terminal CaaX prenylation motif, where a = an aliphatic amino acid and X = any amino acid, and are localized primarily in the cytoplasm. Both are believed to have tumor suppressor activity.