GEM (GTP binding protein overexpressed in skeletal muscle) is a guanosine triphosphate (GTP)-binding protein. It controls voltage gated Ca2+ channels and cytoskeleton dynamics. Overexpression of GEM causes disruption of stress fiber, changes in cell shape and neurite elongation in interphase cells. In addition, it is also involved in actin remodelling during mitosis. In Timothy syndrome, overexpression of GEM leads to inactivation of RhoA, thereby preventing dendritic retraction. GEM might also be associated with cell invasiveness. In HTLV-1 retrovirus (human T-cell leukemia virus type 1) infection, GEM is involved in cell-to-cell viral transmission.
