Inhibits estrogen-induced cell proliferation by competing with PLCG for binding to ESR1, blocking the effect of estrogen on PLCG and repressing estrogen-induced proliferation (By similarity). May play a role in T-cell development and function. Interacts with ESR1. Located at podocyte foot processes. In the kidney, expressed only in the glomerulus. Expressed in T-cells, B-cells, macrophages and dendritic cells (at protein level). In adult, highest levels are found in muscle and lung with lower levels in kidney. Upon CD3/CD28 stimulation in CD4 T-cells.