def _assemble_gef(self, stmt):
        """Example: act(p(HGNC:SOS1), ma(gef)) => act(p(HGNC:KRAS), ma(gtp))"""
        gef = deepcopy(stmt.gef)
        gef.activity = ActivityCondition('gef', True)
        ras = deepcopy(stmt.ras)
        ras.activity = ActivityCondition('gtpbound', True)
        self._add_nodes_edges(gef, ras, pc.DIRECTLY_INCREASES, stmt.evidence)