"The production of new proteins can only occur when the RNA that will make the required proteins is turned on. Until then, the RNA is "locked up" by a silencing molecule, which is a micro RNA. The RNA and micro RNA are part of a package that includes several other proteins...When synapses got activated, one of the proteins wrapped around that silencing complex gets degraded." When the signal comes in, the wrapping protein degrades or gets fragmented. Then the RNA is suddenly free to synthesize a new protein." - bob